詳細

SOFIA LYKAWKA Patryk （ソフィア　リカフィカ　パトリック）

  • 総合社会学部 総合社会学科 社会・マスメディア系専攻　准教授
Last Updated :2024/04/17

コミュニケーション情報 byコメンテータガイド

  • コメント

    「地球の水は小天体によって運ばれたのか？」「なぜ水星と火星は地球に比べて小さい惑星なのか？」こうした謎の真相を追求しよう。また、宇宙の不思議と天文学・科学の影響を社会の視点で考えていきたい。

  • 報道関連出演・掲載一覧

    ＜報道関連出演・掲載一覧＞ 【太陽系外縁部に未発見の惑星がある可能性をシミュレーションで示唆】 ●2023/10/9 　sorae ●2023/9/24 　Forbes ●2023/9/12 　Popular Science ●2023/9/7 　BBC ●2023/9/4 　New York Post ●2023/8/31 　Discover ●2023/8/29 　日刊工業新聞 　その他の記事や詳細は　 https://sites.google.com/site/patryksofialykawka/home/kbp　に掲載

研究者情報

学位

  • 博士（学術）（神戸大学）

ホームページURL

科研費研究者番号

  • 30549853

ORCID ID

J-Global ID

プロフィール

研究キーワード

  • 小惑星   小惑星帯   冥王星   カイパーベルト惑星   惑星X   カオス   火星   水星   エッジワース-カイパーベルト   地球型惑星   軌道共鳴   惑星移動   天体力学   太陽系小天体   太陽系   惑星形成   太陽系外縁天体   惑星科学   

現在の研究分野（キーワード）

    「地球の水は小天体によって運ばれたのか？」「なぜ水星と火星は地球に比べて小さい惑星なのか？」こうした謎の真相を追求しよう。また、宇宙の不思議と天文学・科学の影響を社会の視点で考えていきたい。

研究分野

  • 自然科学一般 / 宇宙惑星科学
  • 人文・社会 / 科学教育
  • 自然科学一般 / 天文学
  • 自然科学一般 / 固体地球科学 / 惑星系・小天体の物理学と力学

経歴

  • 2015年04月 - 現在  近畿大学総合社会学部准教授
  • 2010年04月 - 2015年03月  近畿大学、総合社会学部講師
  • 2009年04月 - 2010年03月  近畿大学、国際人文科学研究所助教
  • 2007年04月 - 2009年03月  神戸大学、自然科学研究科日本学術振興会外国人特別研究員

学歴

  • 2004年04月 - 2007年03月   神戸大学   自然科学研究科   博士課程・地球惑星システム科学

所属学協会

  • 惑星科学部門・米国天文学会   国際天文学連合   日本天文学会   日本惑星科学会   日本地球惑星科学連合   

研究活動情報

論文

  • Patryk Sofia Lykawka; Takashi Ito
    The Astronomical Journal 166 3 118 - 118 2023年08月 
    Abstract The orbits of trans-Neptunian objects (TNOs) can indicate the existence of an undiscovered planet in the outer solar system. Here we used N-body computer simulations to investigate the effects of a hypothetical Kuiper Belt planet (KBP) on the orbital structure of TNOs in the distant Kuiper Belt beyond ∼50 au. We used observations to constrain model results, including the well-characterized Outer Solar System Origins Survey (OSSOS). We determined that an Earth-like planet (m ∼ 1.5–3 M⊕) located on a distant (semimajor axis a ∼ 250–500 au, perihelion q ∼ 200 au) and inclined (i ∼ 30°) orbit can explain three fundamental properties of the distant Kuiper Belt: a prominent population of TNOs with orbits beyond Neptune’s gravitational influence (i.e., detached objects with q > 40 au), a significant population of high-i objects (i > 45°), and the existence of some extreme objects with peculiar orbits (e.g., Sedna). Furthermore, the proposed KBP is compatible with the existence of identified gigayear-stable TNOs in the 2:1, 5:2, 3:1, 4:1, 5:1, and 6:1 Neptunian mean motion resonances. These stable populations are often neglected in other studies. We predict the existence of an Earth-like planet and several TNOs on peculiar orbits in the outer solar system, which can serve as observationally testable signatures of the putative planet’s perturbations.
  • Edward Ashton; Chan-Kao Chang; Ying-Tung Chen; Matthew J. Lehner; Shiang-Yu Wang; Mike Alexandersen; Young-Jun Choi; Wesley C. Fraser; A. Paula Granados Contreras; Takashi Ito; Youngmin JeongAhn; Jianghui Ji; JJ Kavelaars; Myung-Jin Kim; Samantha M. Lawler; Jian Li; Zhong-Yi Lin; Patryk Sofia Lykawka; Hong-Kyu Moon; Surhud More; Marco A. Muñoz-Gutiérrez; Keiji Ohtsuki; Rosemary E. Pike; Tsuyoshi Terai; Seitaro Urakawa; Fumi Yoshida; Hui Zhang; Haibin Zhao; Ji-Lin Zhou
    The Astrophysical Journal Supplement Series 267 2 33 - 33 2023年07月 
    Abstract From the first phase of the high-cadence Formation of the Outer Solar System: an Icy Legacy (FOSSIL) survey, we analyzed lightcurves, ranging from one to four nights in length, of 371 trans-Neptunian objects (TNOs) for periodicity. We found 29 TNOs with periodic lightcurves, one of which is a good candidate for a close/contact binary. Another of the periodic FOSSIL TNOs could potentially have the fastest of all known TNO spin rates, with a period of 1.3 hr. We do not have total confidence in the period and thus plan to obtain a more detailed lightcurve for confirmation. The periodic TNOs have an average rotation period of 11.2 hr, close to the value obtained by Alexandersen et al., which had similar cadence, but different from other surveys. In regards to contention in the literature about whether smaller TNOs are more irregular in shape and thus have larger lightcurve amplitudes, we found that there is a weak correlation between absolute magnitude and lightcurve amplitude in a subset of 194 FOSSIL TNOs, even when using the more appropriate brightest (minimum) absolute magnitude instead of the time-averaged value.
  • Patryk Sofia Lykawka; Takashi Ito
    Scientific Reports 13 1 2023年03月 
    Abstract The terrestrial planets formed by accretion of asteroid-like objects within the inner solar system’s protoplanetary disk. Previous works have found that forming a small-mass Mars requires the disk to contain little mass beyond ~ 1.5 au (i.e., the disk mass was concentrated within this boundary). The asteroid belt also holds crucial information about the origin of such a narrow disk. Several scenarios may produce a narrow disk. However, simultaneously replicating the four terrestrial planets and the inner solar system properties remains elusive. Here, we found that chaotic excitation of disk objects generated by a near-resonant configuration of Jupiter–Saturn can create a narrow disk, allowing the formation of the terrestrial planets and the asteroid belt. Our simulations showed that this mechanism could typically deplete a massive disk beyond ~ 1.5 au on a 5–10 Myr timescale. The resulting terrestrial systems reproduced the current orbits and masses of Venus, Earth and Mars. Adding an inner region disk component within ~ 0.8–0.9 au allowed several terrestrial systems to simultaneously form analogues of the four terrestrial planets. Our terrestrial systems also frequently satisfied additional constraints: Moon-forming giant impacts occurring after a median ~ 30–55 Myr, late impactors represented by disk objects formed within 2 au, and effective water delivery during the first 10–20 Myr of Earth’s formation. Finally, our model asteroid belt explained the asteroid belt’s orbital structure, small mass and taxonomy (S-, C- and D/P-types).
  • Chan-Kao Chang; Ying-Tung Chen; Wesley C. Fraser; Matthew J. Lehner; Shiang-Yu Wang; Mike Alexandersen; Young-Jun Choi; A. Paula Granados Contreras; Takashi Ito; Youngmin JeongAhn; Jianghui Ji; J. J. Kavelaars; Myung-Jin Kim; Samantha M. Lawler; Jian Li; Zhong-Yi Lin; Patryk Sofia Lykawka; Hong-Kyu Moon; Surhud More; Marco Muñoz-Gutiérrez; Keiji Ohtsuki; Rosemary E. Pike; Tsuyoshi Terai; Seitaro Urakawa; Fumi Yoshida; Hui Zhang; Haibin Zhao; Ji-Lin Zhou
    The Astrophysical Journal Supplement Series 259 1 7 - 7 2022年03月 
    Abstract Using the high-cadence lightcurves collected from the FOSSIL survey, rotation periods of 17 small (diameter 1 km < D < 3 km) Hilda asteroids (hereinafter Hildas) were obtained. Combined with the previously measured rotation periods of Hildas, a spin-rate limit appears at around 3 hr. Assuming rubble-pile structures for the Hildas, a bulk density of ∼1.5 g cm−3 is required to withstand this spin-rate limit. This value is similar to that of the C-type asteroids (1.33 g cm−3) and higher than the ∼1 g cm−3 bulk density of the Jupiter Trojans. This suggests that the Hildas population may contain more C-type asteroids than expected, and the limit at 3 hr simply reflects the spin-rate limit for C-type asteroids. In addition, a Hilda superfast rotator was found, which has a rotation period of 1.633 hr and an estimated diameter of 0.7 km. This object is unlikely to be explained by a rubble-pile or monolithic structure.
  • Chan-Kao Chang; Ying-Tung Chen; Wesley C. Fraser; Fumi Yoshida; Matthew J. Lehner; Shiang-Yu Wang; JJ Kavelaars; Rosemary E. Pike; Mike Alexandersen; Takashi Ito; Young-Jun Choi; A. Paula Granados Contreras; Youngmin JeongAhn; Jianghui Ji; Myung-Jin Kim; Samantha M. Lawler; Jian Li; Zhong-Yi Lin; Patryk Sofia Lykawka; Hong-Kyu Moon; Surhud More; Marco A. Muñoz-Gutiérrez; Keiji Ohtsuki; Tsuyoshi Terai; Seitaro Urakawa; Hui Zhang; Haibin Zhao; Ji-Lin Zhou
    The Planetary Science Journal 2 5 191 - 191 2021年10月 
    Rotation periods of 53 small (diameters 2 km < D < 40 km) Jupiter Trojans (JTs) were derived using the highcadence lightcurves obtained by the FOSSIL phase I survey, a Subaru/Hyper Suprime-Cam intensive program. These are the first reported periods measured for JTs with D < 10 km. We found a lower limit of the rotation period near 4 hr, instead of the previously published result of 5 hr found for larger JTs. Assuming a rubble-pile structure for JTs, a bulk density of ≈ 0.9 g cm-3 is required to withstand this spin rate limit, consistent with the value ~0.8-1.0 g cm-3 derived from the binary JT system, (617) Patroclus-Menoetius system.
  • Fumi Yoshida; Tsuyoshi Terai; Takashi Ito; Keiji Ohtsuki; Patryk Sofia Lykawka; Takahiro Hiroi; Naruhisa Takato
    Planetary and Space Science 190 2020年10月 
    © 2020 Elsevier Ltd The authors regret that we found several typographic errors and inconsistencies in figures in the above article. Specifically, we would like make corrections in Abstract, Figs. 3, 5, 6, and References. All of the corrections are minor, and none of them gives any serious impacts on the discussions or conclusions of the article. The authors would like to apologize for any inconvenience caused.
  • J. Horner; S. R. Kane; J. P. Marshall; P. A. Dalba; T. R. Holt; J. Wood; H. E. Maynard-Casely; R. Wittenmyer; P. S. Lykawka; M. Hill; R. Salmeron; J. Bailey; T. Löhne; M. Agnew; B. D. Carter; C. C.E. Tylor
    Publications of the Astronomical Society of the Pacific 132 1016 1 - 115 2020年10月 
    © 2020. The Astronomical Society of the Pacific. Printed in the U.S.A. Over the past three decades, we have witnessed one of the great revolutions in our understanding of the cosmos— the dawn of the Exoplanet Era. Where once we knew of just one planetary system (the solar system), we now know of thousands, with new systems being announced on a weekly basis. Of the thousands of planetary systems we have found to date, however, there is only one that we can study up-close and personal—the solar system. In this review, we describe our current understanding of the solar system for the exoplanetary science community—with a focus on the processes thought to have shaped the system we see today. In section one, we introduce the solar system as a single well studied example of the many planetary systems now observed. In section two, we describe the solar systemʼs small body populations as we know them today—from the two hundred and five known planetary satellites to the various populations of small bodies that serve as a reminder of the systemʼs formation and early evolution. In section three, we consider our current knowledge of the solar systemʼs planets, as physical bodies. In section four we discuss the research that has been carried out into the solar systemʼs formation and evolution, with a focus on the information gleaned as a result of detailed studies of the systemʼs small body populations. In section five, we discuss our current knowledge of planetary systems beyond our own—both in terms of the planets they host, and in terms of the debris that we observe orbiting their host stars. As we learn ever more about the diversity and ubiquity of other planetary systems, our solar system will remain the key touchstone that facilitates our understanding and modeling of those newly found systems, and we finish section five with a discussion of the future surveys that will further expand that knowledge.
  • Fumi Yoshida; Tsuyoshi Terai; Takashi Ito; Keiji Ohtsuki; Patryk Sofia Lykawka; Takahiro Hiroi; Naruhisa Takato
    PLANETARY AND SPACE SCIENCE 190 2020年10月 
    The authors regret that we found several typographic errors and inconsistencies in figures in the above article. Specifically, we would like make corrections in Abstract, Figs. 3, 5, 6, and References. All of the corrections are minor, and none of them gives any serious impacts on the discussions or conclusions of the article. The authors would like to apologize for any inconvenience caused.
  • Patryk Sofia Lykawka
    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 496 3 3688 - 3699 2020年06月 
    A successful solar system model must reproduce the four terrestrial planets. Here, we focus on 1) the likelihood of forming Mercury and the four terrestrial planets in the same system (a 4-P system); 2) the orbital properties and masses of each terrestrial planet; and 3) the timing of Earth's last giant impact and the mass accreted by our planet thereafter. Addressing these constraints, we performed 450 N-body simulations of terrestrial planet formation based on narrow protoplanetary disks with mass confined to 0.7-1.0 au. We identified 164 analogue systems, but only 24 systems contained Mercury analogues, and eight systems were 4-P ones. We found that narrow disks containing a small number of embryos with individual masses comparable to that of Mars and the giant planets on their current orbits yielded the best prospects for satisfying those constraints. However, serious shortcomings remain. The formation of Mercury analogues and 4-P systems was too inefficient (5% and 2%, respectively), and most Venus-to-Earth analogue mass ratios were incorrect. Mercury and Venus analogues also formed too close to each other (~0.15-0.21 au) compared to reality (0.34 au). Similarly, the mutual distances between the Venus and Earth analogues were greater than those observed (0.34 vs. 0.28 au). Furthermore, the Venus-Earth pair was not reproduced in orbital-mass space statistically. Overall, our results suggest serious problems with using narrow disks to explain the inner solar system. In particular, the formation of Mercury remains an outstanding problem for terrestrial planet formation models.
  • Ying Tung Chen; Brett Gladman; Kathryn Volk; Ruth Murray-Clay; Matthew J. Lehner; J. J. Kavelaars; Shiang Yu Wang; Hsing Wen Lin; Patryk Sofia Lykawka; Mike Alexandersen; Michele T. Bannister; Samantha M. Lawler; Rebekah I. Dawson; Sarah Greenstreet; Stephen D.J. Gwyn; Jean Marc Petit
    Astrophysical Journal 158 5 2019年11月 
    © 2019. The American Astronomical Society. All rights reserved. Resonant dynamics plays a significant role in the past evolution and current state of our outer solar system. The population ratios and spatial distribution of Neptune's resonant populations are direct clues to understanding the history of our planetary system. The orbital structure of the objects in Neptune's 2:1 mean-motion resonance (“twotinos”) has the potential to be a tracer of planetary migration processes. Different migration processes produce distinct architectures, recognizable by well-characterized surveys. However, previous characterized surveys only discovered a few twotinos, making it impossible to model the intrinsic twotino population. With a well-designed cadence and nearly 100% tracking success, the Outer Solar System Origins Survey (OSSOS) discovered 838 trans-Neptunian objects, of which 34 are securely twotinos with well-constrained libration angles and amplitudes. We use the OSSOS twotinos and the survey characterization parameters via the OSSOS survey simulator to inspect the intrinsic population and orbital distributions of twotinos. The estimated twotino population, 4400-+11001500 with Hr < 8.66 (diameter ∼100 km) at 95% confidence, is consistent with the previous low-precision estimate. We also constrain the width of the inclination distribution to a relatively narrow value of si = 6-°+11 and find that the eccentricity distribution is consistent with a Gaussian centered on ec = 0.275 with a width ew = 0.06. We find a single-slope exponential luminosity function with α = 0.6 for the twotinos. Finally, for the first time, we meaningfully constrain the fraction of symmetric twotinos and the ratio of the leading asymmetric islands; both fractions are in the range of 0.2-0.6. These measurements rule out certain theoretical models of Neptune's migration history.
  • Patryk Sofia Lykawka; Takashi Ito
    The Astrophysical Journal 883 2 130  American Astronomical Society 2019年10月 [査読有り]
     
    © 2019. The American Astronomical Society. All rights reserved. To reproduce the orbits and masses of the terrestrial planets (analogs) of the solar system, most studies scrutinize simulations for success as a batch. However, there is insufficient discussion in the literature on the likelihood of forming planet analogs simultaneously in the same system (analog system). To address this issue, we performed 540 N-body simulations of protoplanetary disks representative of typical models in the literature. We identified a total of 194 analog systems containing at least three analogs, but only 17 systems simultaneously contained analogs of the four terrestrial planets. From an analysis of our analog systems, we found that, compared to the real planets, truncated disks based on typical outcomes of the Grand Tack model produced analogs of Mercury and Mars that were too dynamically cold and located too close to the Venus and Earth analogs. Additionally, all the Mercury analogs were too massive, while most of the Mars analogs were more massive than Mars. Furthermore, the timing of the Moon-forming impact was too early in these systems, and the amount of additional mass accreted after the event was too great. Therefore, such truncated disks cannot explain the formation of the terrestrial planets. Our results suggest that forming the four terrestrial planets requires disks with the following properties: (1) mass concentrated in narrow core regions between ∼0.7-0.9 au and ∼1.0-1.2 au, (2) an inner region component starting at ∼0.3-0.4 au, (3) a less massive component beginning at ∼1.0-1.2 au, (4) embryos rather than planetesimals carrying most of the disk mass, and (5) Jupiter and Saturn placed on eccentric orbits.
  • Fumi Yoshida; Tsuyoshi Terai; Takashi Ito; Keiji Ohtsuki; Patryk Sofia Lykawka; Takahiro Hiroi; Naruhisa Takato
    Planetary and Space Science 169 78 - 85 2019年05月 [査読有り]
     
    © 2019 Elsevier Ltd Since 2002, we have obtained size frequency distributions (SFDs) of main belt asteroids (MBAs), Hildas, and Jupiter Trojans (JTs) by using the 8.2-m Subaru Telescope equipped with the wide-field CCD cameras: Suprime-Cam (SC) or Hyper Suprime-Cam (HSC). After combining these SFDs with SFDs obtained from other surveys, we performed a comparative study of SFDs for each group of small bodies in an attempt to obtain clues about planet migration that affected those populations. The large aperture of the Subaru Telescope and the wide field of view of SC or HSC allowed us to detect small moving objects up to apparent magnitudes 24.4–24.5 mag (Rc-band), which corresponds to sub–km in diameter (D) for MBAs and about 1 km for Hildas and JTs. We combined the SFDs obtained from our surveys with those derived from published data to obtain the individual representative SFD for MBAs, Hildas and JTs in the size range of sub–km to 1000 km. We found that the SFDs of JTs and Hildas are roughly flat in the R-plot while that of MBAs has a wavy structure. We also investigated the SFDs of MBAs in the inner, middle, and outer regions of the main belt. We found that the shape of the SFDs changes gradually with increasing heliocentric distance across these regions. This trend continues beyond the outer region, where the SFD becomes flatter as shown by the SFDs of JTs and Hildas. Recent planet migration models suggest that the current JTs originated in the trans-Neptunian region and were captured as Trojans during planet migration. The finding of a gradual change of the SFDs from the inner MBAs to JTs is in line with the idea that trans-Neptunian objects (TNOs) were implanted not only into the JT region, but also into the main belt outer region (including the Hildas) at the early solar system. In order to investigate this implantation hypothesis, we considered a synthetic population of TNOs assuming with a SFD represented by a power-law distribution of N>D∝D-3, (estimated from crater record on Pluto and Charon). We then added this synthetic population to the MBA populations in various proportions. We found that the higher the proportion, the flatter the wavy SFD of MBAs becomes. This simple model yields a rough explanation for the gradual change of SFDs found from the inner main belt to the JT region. However, the shape of the modelled SFDs does not match observations for all sizes. In particular, because important discrepancies are seen in the small size range, we need to consider the removal of small objects by collisional evolution and/or Yarkovsky effect in the future.
  • E. Vilenius; J. Stansberry; T. Müller; M. Mueller; C. Kiss; P. Santos-Sanz; M. Mommert; A. Pál; E. Lellouch; J. L. Ortiz; N. Peixinho; A. Thirouin; P. S. Lykawka; J. Horner; R. Duffard; S. Fornasier; A. Delsanti
    ASTRONOMY & ASTROPHYSICS 618 2019年04月 [査読有り]
     
    A group of trans-Neptunian objects (TNO) are dynamically related to the dwarf planet 136108 Haumea. Ten of them show strong indications of water ice on their surfaces, are assumed to have resulted from a collision, and are accepted as the only known TNO collisional family. Nineteen other dynamically similar objects lack water ice absorptions and are hypothesized to be dynamical interlopers. We have made observations to determine sizes and geometric albedos of six of the accepted Haumea family members and one dynamical interloper. Ten other dynamical interlopers have been measured by previous works. We compare the individual and statistical properties of the family members and interlopers, examining the size and albedo distributions of both groups. We also examine implications for the total mass of the family and their ejection velocities. We use far-infrared space-based telescopes to observe the target TNOs near their thermal peak and combine these data with optical magnitudes to derive sizes and albedos using radiometric techniques. We determine the power-law slope of ejection velocity as a function of effective diameter. The detected Haumea family members have a diversity of geometric albedos $\sim$ 0.3-0.8, which are higher than geometric albedos of dynamically similar objects without water ice. The median geometric albedo for accepted family members is $p_V=0.48_{-0.18}^{+0.28}$, compared to 0.08$_{-0.05}^{+0.07}$ for the dynamical interlopers. In the size range $D=175-300$ km, the slope of the cumulative size distribution is $q$=3.2$_{-0.4}^{+0.7}$ for accepted family members, steeper than the $q$=2.0$\pm$0.6 slope for the dynamical interlopers with D$< $500 km. The total mass of Haumea's moons and family members is 2.4% of Haumea's mass. The ejection velocities required to emplace them on their current orbits show a dependence on diameter, with a power-law slope of 0.21-0.50.
  • Haruka Sakugawa; Tsuyoshi Terai; Keiji Ohtsuki; Fumi Yoshida; Naruhisa Takato; Patryk Sofia Lykawka; Shiang Yu Wang
    Publications of the Astronomical Society of Japan 70 6 2018年12月 [査読有り]
     
    © The Author(s) 2018. Centaurs have orbits between Jupiter and Neptune and are thought to originate from the trans-Neptunian region. Observations of surface properties of Centaurs and comparison with those of trans-Neptunian objects (TNOs) would provide constraints on their origin and evolution.We analyzed imaging data of nine known Centaurs observed by the Hyper Suprime-Cam (HSC) installed on the Subaru Telescope with the g- and i-band filters. Using the data available in the public HSC data archive, as well as those obtained by the HSC Subaru Strategic Program (HSC-SSP) by the end of 2017 June, we obtained the g - i colors of the nine Centaurs. We compared them with those of known TNOs in the HSC-SSP data obtained by T. Terai et al. (2018, PASJ, 70, S40). We found that the color distribution of the nine Centaurs is similar to that of those TNOs with high orbital inclinations, but distinct from those TNOs with low orbital inclinations.We also examined correlations between the colors of these Centaurs and their orbital elements and absolute magnitude. The Centaurs' colors show a moderate positive correlation with semi-major axis, while no significant correlations between the color and other orbital elements or absolute magnitude were found for these Centaurs. On the other hand, recent studies on Centaurs with larger samples show interesting correlations between their color and absolute magnitude or orbital inclination. We discuss how our data fit in these previous studies, and also discuss implications of these results for their origin and evolution.
  • Tatsuaki Okada; Yoko Kebukawa; Jun Aoki; Jun Matsumoto; Hajime Yano; Takahiro Iwata; Osamu Mori; Jean-Pierre Bibring; Stephan Ulamec; Ralf Jaumann
    Planetary and Space Science 161 99 - 106 2018年10月
  • E. Vilenius; J. Stansberry; T. Müller; M. Mueller; C. Kiss; P. Santos-Sanz; M. Mommert; A. Pál; E. Lellouch; J. L. Ortiz; N. Peixinho; A. Thirouin; P. S. Lykawka; J. Horner; R. Duffard; S. Fornasier; A. Delsanti
    Astronomy and Astrophysics 618 2018年10月 
    © ESO 2018. Context. A group of trans-Neptunian objects (TNOs) are dynamically related to the dwarf planet 136108 Haumea. Ten of them show strong indications of water ice on their surfaces, are assumed to have resulted from a collision, and are accepted as the only known TNO collisional family. Nineteen other dynamically similar objects lack water ice absorptions and are hypothesized to be dynamical interlopers. Aims. We have made observations to determine sizes and geometric albedos of six of the accepted Haumea family members and one dynamical interloper. Ten other dynamical interlopers have been measured by previous works. We compare the individual and statistical properties of the family members and interlopers, examining the size and albedo distributions of both groups. We also examine implications for the total mass of the family and their ejection velocities. Methods. We use far-infrared space-based telescopes to observe the target TNOs near their thermal peak and combine these data with optical magnitudes to derive sizes and albedos using radiometric techniques. Using measured and inferred sizes together with ejection velocities, we determine the power-law slope of ejection velocity as a function of effective diameter. Results. The detected Haumea family members have a diversity of geometric albedos 0.3-0.8, which are higher than geometric albedos of dynamically similar objects without water ice. The median geometric albedo for accepted family members is pV = 0.48-0.18+0.28, compared to 0.08-0.05+0.07 for the dynamical interlopers. In the size range D = 175-300 km, the slope of the cumulative size distribution is q = 3.2-0.4+0.7 for accepted family members, steeper than the q = 2.0 ± 0.6 slope for the dynamical interlopers with D < 500 km. The total mass of Haumea's moons and family members is 2.4% of Haumea's mass. The ejection velocities required to emplace them on their current orbits show a dependence on diameter, with a power-law slope of 0.21-0.50.
  • Kathryn Volk; Ruth A. Murray-Clay; Brett J. Gladman; Samantha M. Lawler; Tze Yeung Mathew Yu; Mike Alexandersen; Michele T. Bannister; Ying Tung Chen; Rebekah I. Dawson; Sarah Greenstreet; Stephen D.J. Gwyn; J. J. Kavelaars; Hsing Wen Lin; Patryk Sofia Lykawka; Jean Marc Petit
    Astronomical Journal 155 6 2018年06月 [査読有り]
     
    © 2018. The American Astronomical Society. All rights reserved. We discuss the detection in the Outer Solar System Origins Survey (OSSOS) of two objects in Neptune's distant 9:1 mean motion resonance at semimajor axis a ≈ 130 au. Both objects are securely resonant on 10 Myr timescales, with one securely in the 9:1 resonance's leading asymmetric libration island and the other in either the symmetric or trailing asymmetric island. These objects are the largest semimajor axis objects with secure resonant classifications, and their detection in a carefully characterized survey allows for the first robust resonance population estimate beyond 100 au. The detection of these objects implies a 9:1 resonance population of 1.1 × 104 objects with H r < 8.66 (D100 km) on similar orbits (95% confidence range of ∼(0.4-3) × 104). Integrations over 4 Gyr of an ensemble of clones spanning these objects' orbit-fit uncertainties reveal that they both have median resonance occupation timescales of ∼1 Gyr. These timescales are consistent with the hypothesis that these objects originate in the scattering population but became transiently stuck to Neptune's 9:1 resonance within the last ∼1 Gyr of solar system evolution. Based on simulations of a model of the current scattering population, we estimate the expected resonance sticking population in the 9:1 resonance to be 1000-4500 objects with H r < 8.66; this is marginally consistent with the OSSOS 9:1 population estimate. We conclude that resonance sticking is a plausible explanation for the observed 9:1 population, but we also discuss the possibility of a primordial 9:1 population, which would have interesting implications for the Kuiper Belt's dynamical history.
  • Michele T. Bannister; Brett J. Gladman; J. J. Kavelaars; Jean Marc Petit; Kathryn Volk; Ying Tung Chen; Mike Alexandersen; Stephen D.J. Gwyn; Megan E. Schwamb; Edward Ashton; Susan D. Benecchi; Nahuel Cabral; Rebekah I. Dawson; Audrey Delsanti; Wesley C. Fraser; Mikael Granvik; Sarah Greenstreet; Aurélie Guilbert-Lepoutre; Wing Huen Ip; Marian Jakubik; R. Lynne Jones; Nathan A. Kaib; Pedro Lacerda; Christa Van Laerhoven; Samantha Lawler; Matthew J. Lehner; Hsing Wen Lin; Patryk Sofia Lykawka; Michaël Marsset; Ruth Murray-Clay; Rosemary E. Pike; Philippe Rousselot; Cory Shankman; Audrey Thirouin; Pierre Vernazza; Shiang Yu Wang
    Astrophysical Journal, Supplement Series 236 1 2018年05月 [査読有り]
     
    © 2018. The American Astronomical Society. All rights reserved. The Outer Solar System Origins Survey (OSSOS), a wide-field imaging program in 2013-2017 with the Canada-France-Hawaii Telescope, surveyed 155 deg2 of sky to depths of m r = 24.1-25.2. We present 838 outer solar system discoveries that are entirely free of ephemeris bias. This increases the inventory of trans-Neptunian objects (TNOs) with accurately known orbits by nearly 50%. Each minor planet has 20-60 Gaia/Pan-STARRS-calibrated astrometric measurements made over 2-5 oppositions, which allows accurate classification of their orbits within the trans-Neptunian dynamical populations. The populations orbiting in mean-motion resonance with Neptune are key to understanding Neptune's early migration. Our 313 resonant TNOs, including 132 plutinos, triple the available characterized sample and include new occupancy of distant resonances out to semimajor axis a ∼ 130 au. OSSOS doubles the known population of the nonresonant Kuiper Belt, providing 436 TNOs in this region, all with exceptionally high-quality orbits of a uncertainty σ a ≤ 0.1%; they show that the belt exists from a 37 au, with a lower perihelion bound of 35 au. We confirm the presence of a concentrated low-inclination a ≃ 44 au "kernel" population and a dynamically cold population extending beyond the 2:1 resonance. We finely quantify the survey's observational biases. Our survey simulator provides a straightforward way to impose these biases on models of the trans-Neptunian orbit distributions, allowing statistical comparison to the discoveries. The OSSOS TNOs, unprecedented in their orbital precision for the size of the sample, are ideal for testing concepts of the history of giant planet migration in the solar system.
  • Tsuyoshi Terai; Fumi Yoshida; Keiji Ohtsuki; Patryk Sofia Lykawka; Naruhisa Takato; Arika Higuchi; Takashi Ito; Yutaka Komiyama; Satoshi Miyazaki; Shiang-Yu Wang
    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN 70 Special Issue 1 2018年01月 [査読有り]
     
    We present visible multi-band photometry of trans-Neptunian objects (TNOs) observed by the Subaru Telescope in the framework of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) from 2014 March to 2016 September. We measured the five broad-band (g, r, i, z, and Y) colors over the wavelength range from 0.4 mu m to 1.0 mu m for 30 known TNOs using the HSC-SSP survey data covering similar to 500 deg(2) of sky within +/- 30 degrees of ecliptic latitude. This dataset allows us to investigate the correlations between the dynamical classes and visible reflectance spectra of TNOs. Our results show that the hot classical and scattered populations with orbital inclination (I) of I greater than or similar to 6 degrees share similar color distributions, while the cold classical population with I less than or similar to 6 degrees has a different color distribution from the others. The low-I population has reflectance increasing toward longer wavelengths up to similar to 0.8 mu m, with a steeper slope than the high-I population at less than or similar to 0.6 mu m. We also find a significant anti-correlation between g - r/r - i colors and inclination in the high-I population, as well as a possible bimodality in the g - i color vs. eccentricity plot.
  • Patryk Sofia Lykawka; Takashi Ito
    The Astrophysical Journal 838 2 106  American Astronomical Society 2017年04月 [査読有り]
     
    © 2017. The American Astronomical Society. All rights reserved. How the four terrestrial planets of the solar system formed is one of the most fundamental questions in the planetary sciences. Particularly, the formation of Mercury remains poorly understood. We investigated terrestrial planet formation by performing 110 high-resolution N-body simulation runs using more than 100 embryos and 6000 disk planetesimals representing a primordial protoplanetary disk. To investigate the formation of Mercury, these simulations considered an inner region of the disk at 0.2-0.5 au (the Mercury region) and disks with and without mass enhancements beyond the ice line location, a IL, in the disk, where a IL = 1.5, 2.25, and 3.0 au were tested. Although Venus and Earth analogs (considering both orbits and masses) successfully formed in the majority of the runs, Mercury analogs were obtained in only nine runs. Mars analogs were also similarly scarce. Our Mercury analogs concentrated at orbits with a ∼ 0.27-0.34 au, relatively small eccentricities/inclinations, and median mass m ∼ 0.2 M⊙. In addition, we found that our Mercury analogs acquired most of their final masses from embryos/planetesimals initially located between 0.2 and ∼1-1.5 au within 10 Myr, while the remaining mass came from a wider region up to ∼3 au at later times. Although the ice line was negligible in the formation of planets located in the Mercury region, it enriched all terrestrial planets with water. Indeed, Mercury analogs showed a wide range of water mass fractions at the end of terrestrial planet formation.
  • Michele T. Bannister; Mike Alexandersen; Susan D. Benecchi; Ying Tung Chen; Audrey Delsanti; Wesley C. Fraser; Brett J. Gladman; Mikael Granvik; Will M. Grundy; Aurélie Guilbert-Lepoutre; Stephen D.J. Gwyn; Wing Huen Ip; Marian Jakubik; R. Lynne Jones; Nathan Kaib; J. J. Kavelaars; Pedro Lacerda; Samantha Lawler; Matthew J. Lehner; Hsing Wen Lin; Patryk Sofia Lykawka; Michael Marsset; Ruth Murray-Clay; Keith S. Noll; Alex Parker; Jean Marc Petit; Rosemary E. Pike; Philippe Rousselot; Megan E. Schwamb; Cory Shankman; Peter Veres; Pierre Vernazza; Kathryn Volk; Shiang Yu Wang; Robert Weryk
    Astronomical Journal 152 6 212 - 212 2016年12月 [査読有り]
     
    © 2016. The American Astronomical Society. All rights reserved. We report the discovery and orbit of a new dwarf planet candidate, 2015 RR245, by the Outer Solar System Origins Survey (OSSOS). The orbit of 2015 RR245 is eccentric (e = 0.586), with a semimajor axis near 82 au, yielding a perihelion distance of 34 au. 2015 RR245 has g - r = 0.59 ± 0.11 and absolute magnitude Hr = 3.6 ± 0.1; for an assumed albedo of pV = 12%, the object has a diameter of ∼670 km. Based on astrometric measurements from OSSOS and Pan-STARRS1, we find that 2015 RR245 is securely trapped on ten-megayear timescales in the 9:2 mean-motion resonance with Neptune. It is the first trans-Neptunian object (TNO) identified in this resonance. On hundred-megayear timescales, particles in 2015 RR245-like orbits depart and sometimes return to the resonance, indicating that 2015 RR245 likely forms part of the long-lived metastable population of distant TNOs that drift between resonance sticking and actively scattering via gravitational encounters with Neptune. The discovery of a 9:2 TNO stresses the role of resonances in the long-term evolution of objects in the scattering disk and reinforces the view that distant resonances are heavily populated in the current solar system. This object further motivates detailed modeling of the transient sticking population.
  • Michele T. Bannister; J. J. Kavelaars; Jean Marc Petit; Brett J. Gladman; Stephen D.J. Gwyn; Ying Tung Chen; Kathryn Volk; Mike Alexandersen; Susan D. Benecchi; Audrey Delsanti; Wesley C. Fraser; Mikael Granvik; Will M. Grundy; Aurélie Guilbert-Lepoutre; Daniel Hestroffer; Wing Huen Ip; Marian Jakubik; R. Lynne Jones; Nathan Kaib; Catherine F. Kavelaars; Pedro Lacerda; Samantha Lawler; Matthew J. Lehner; Hsing Wen Lin; Tim Lister; Patryk Sofia Lykawka; Stephanie Monty; Michael Marsset; Ruth Murray-Clay; Keith S. Noll; Alex Parker; Rosemary E. Pike; Philippe Rousselot; David Rusk; Megan E. Schwamb; Cory Shankman; Bruno Sicardy; Pierre Vernazza; Shiang Yu Wang
    Astronomical Journal 152 3 2016年09月 [査読有り]
     
    © 2016. The American Astronomical Society. All rights reserved. We report the discovery, tracking, and detection circumstances for 85 trans-Neptunian objects (TNOs) from the first 42 deg2 of the Outer Solar System Origins Survey. This ongoing r-band solar system survey uses the 0.9 deg2 field of view MegaPrime camera on the 3.6 m Canada-France-Hawaii Telescope. Our orbital elements for these TNOs are precise to a fractional semimajor axis uncertainty <0.1%. We achieve this precision in just two oppositions, as compared to the normal three to five oppositions, via a dense observing cadence and innovative astrometric technique. These discoveries are free of ephemeris bias, a first for large trans-Neptunian surveys. We also provide the necessary information to enable models of TNO orbital distributions to be tested against our TNO sample. We confirm the existence of a cold "kernel" of objects within the main cold classical Kuiper Belt and infer the existence of an extension of the "stirred" cold classical Kuiper Belt to at least several au beyond the 2:1 mean motion resonance with Neptune. We find that the population model of Petit et al. remains a plausible representation of the Kuiper Belt. The full survey, to be completed in 2017, will provide an exquisitely characterized sample of important resonant TNO populations, ideal for testing models of giant planet migration during the early history of the solar system.
  • Kathryn Volk; Ruth Murray-Clay; Brett Gladman; Samantha Lawler; Michele T. Bannister; J. J. Kavelaars; Jean-Marc Petit; Stephen Gwyn; Mike Alexandersen; Ying-Tung Chen; Patryk Sofia Lykawka; Wing Ip; Hsing Wen Lin
    The Astronomical Journal 152 1 23 - 23 American Astronomical Society 2016年07月 [査読有り]
     
    © 2016. The American Astronomical Society. All rights reserved. The first two observational sky "blocks" of the Outer Solar System Origins Survey (OSSOS) have significantly increased the number of well characterized observed trans-Neptunian objects (TNOs) in Neptune's mean motion resonances. We describe the 31 securely resonant TNOs detected by OSSOS so far, and we use them to independently verify the resonant population models from the Canada-France Ecliptic Plane Survey (CFEPS), with which we find broad agreement. We confirm that the 5:2 resonance is more populated than models of the outer solar system's dynamical history predict; our minimum population estimate shows that the high-eccentricity (e > 0.35) portion of the resonance is at least as populous as the 2:1 and possibly as populated as the 3:2 resonance. One OSSOS block was well suited for detecting objects trapped at low libration amplitudes in Neptune's 3:2 resonance, a population of interest in testing the origins of resonant TNOs. We detected three 3:2 objects with libration amplitudes below the cutoff modeled by CFEPS; OSSOS thus offers new constraints on this distribution. The OSSOS detections confirm that the 2:1 resonance has a dynamically colder inclination distribution than either the 3:2 or 5:2 resonances. Using the combined OSSOS and CFEPS 2:1 detections, we constrain the fraction of 2:1 objects in the symmetric mode of libration to 0.2-0.85; we also constrain the fraction of asymmetric librators in the leading island, which has been theoretically predicted to vary depending on Neptune's migration history, to be 0.05-0.8. Future OSSOS blocks will improve these constraints.
  • Jonathan Horner; Patryk Sofia Lykawka
    arXiv preprint arXiv:1601.00383 2016年01月 [査読有り]
     
    The Neptune Trojans are the most recent addition to the panoply of Solar system small body populations. The orbit of the first discovered member, 2001 QR$_{322}$, was investigated shortly after its discovery, based on early observations of the object, and it was found to be dynamically stable on timescales comparable to the age of the Solar system. As further observations were obtained of the object over the following years, the best-fit solution for its orbit changed. We therefore carried out a new study of 2001 QR$_{322}$'s orbit in 2010, finding that it lay on the boundary between dynamically stable and unstable regions in Neptune's Trojan cloud, and concluding that further observations were needed to determine the true stability of the object's orbit. Here we follow up on that earlier work, and present the preliminary results of a dynamical study using an updated fit to 2001 QR$_{322}$'s orbit. Despite the improved precision with which the orbit of 2001 QR$_{322}$ is known, we find that the best-fit solution remains balanced on a knife-edge, lying between the same regions of stability and instability noted in our earlier work. In the future, we intend to carry out new observations that should hopefully refine the orbit to an extent that its true nature can finally be disentangled.
  • Jonathan Horner; Patryk Sofia Lykawka
    2016年01月 
    The Neptune Trojans are the most recent addition to the panoply of Solar system small body populations. The orbit of the first discovered member, 2001 QR$_{322}$, was investigated shortly after its discovery, based on early observations of the object, and it was found to be dynamically stable on timescales comparable to the age of the Solar system. As further observations were obtained of the object over the following years, the best-fit solution for its orbit changed. We therefore carried out a new study of 2001 QR$_{322}$'s orbit in 2010, finding that it lay on the boundary between dynamically stable and unstable regions in Neptune's Trojan cloud, and concluding that further observations were needed to determine the true stability of the object's orbit. Here we follow up on that earlier work, and present the preliminary results of a dynamical study using an updated fit to 2001 QR$_{322}$'s orbit. Despite the improved precision with which the orbit of 2001 QR$_{322}$ is known, we find that the best-fit solution remains balanced on a knife-edge, lying between the same regions of stability and instability noted in our earlier work. In the future, we intend to carry out new observations that should hopefully refine the orbit to an extent that its true nature can finally be disentangled.
  • Bannister, Michele T; Kavelaars, JJ; Petit, Jean-Marc; Gladman, Brett J; Gwyn, Stephen DJ; Chen, Ying-Tung; Volk, Kathryn; Alex; ersen, Mike; Benecchi, Susan; Delsanti, Audrey; others
    arXiv preprint arXiv:1511.02895 2015年 [査読有り]
  • T. Michikami; A. Hagermann; H. Miyamoto; S. Miura; J. Haruyama; P. S. Lykawka
    Planetary and Space Science 96 71 - 80 2014年06月 [査読有り]
     
    High-resolution images reveal that numerous pit craters exist on the surface of Mars. For some pit craters, the depth-to-diameter ratios are much greater than for ordinary craters. Such deep pit craters are generally considered to be the results of material drainage into a subsurface void space, which might be formed by a lava tube, dike injection, extensional fracturing, and dilational normal faulting. Morphological studies indicate that the formation of a pit crater might be triggered by the impact event, and followed by collapse of the ceiling. To test this hypothesis, we carried out laboratory experiments of impact cratering into brittle targets with variable roof thickness. In particular, the effect of the target thickness on the crater formation is studied to understand the penetration process by an impact. For this purpose, we produced mortar targets with roof thickness of 1-6 cm, and a bulk density of 1550 kg/m3 by using a mixture of cement, water and sand (0.2 mm) in the ratio of 1:1:10, by weight. The compressive strength of the resulting targets is 3.2±0.9 MPa. A spherical nylon projectile (diameter 7 mm) is shot perpendicularly into the target surface at the nominal velocity of 1.2 km/s, using a two-stage light-gas gun. Craters are formed on the opposite side of the impact even when no target penetration occurs. Penetration of the target is achieved when craters on the opposite sides of the target connect with each other. In this case, the cross section of crater somehow attains a flat hourglass-like shape. We also find that the crater diameter on the opposite side is larger than that on the impact side, and more fragments are ejected from the crater on the opposite side than from the crater on the impact side. This result gives a qualitative explanation for the observation that the Martian deep pit craters lack a raised rim and have the ejecta deposit on their floor instead. © 2014 Elsevier Ltd. All rights reserved.
  • Lykawka Patryk Sofia; Ito Takashi
    Proceedings of the ISAS Lunar and Planetary Symposium 46 8p  2014年 [査読有り]
  • Patryk Sofia Lykawka; Takashi Ito
    The Astrophysical Journal 773 1 65 - 65 American Astronomical Society 2013年08月 [査読有り]
     
    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ∼ 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths). © 2013. The American Astronomical Society. All rights reserved.
  • Lykawka Patryk Sofia; Ito Takashi
    Proceedings of the ISAS Lunar and Planetary Symposium 46 1 8p - 65 Institute of Space and Astronautical Science, JAXA ; [2006]- 2013年06月 [査読有り]
     
    The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ~1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to present-day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars' mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars' small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths).
  • 平成24 年度国立天文台天文シミュレーションプロジェクト成果報告書
    パトリック ソフィア リカフィカ
    2013年04月 
    有無自己重力の微惑星円盤による惑星と小天体の軌道進化 Dynamical evolution of planets and small bodies in massive planetesimal disks with and without self-gravity
  • LYKAWKA Patryk Sofia; HORNER Jonathan; MUELLER Thomas
    スペースガード研究 5 5 13 - 16 2013年02月
  • Jonathan Horner; F. Elliott Koch; Patryk Sofia Lykawka
    arXiv preprint arXiv:1302.2304 2013年02月 [査読有り]
     
    It is now accepted that the Solar system's youth was a dynamic and chaotic time. The giant planets migrated significant distances to reach their current locations, and evidence of that migration's influence on the Solar system abounds. That migration's pace, and the distance over which it occurred, is still heavily debated. Some models feature systems in which the giant planets were initially in an extremely compact configuration, in which Uranus and Neptune are chaotically scattered into the outer Solar system. Others feature architectures that were initially more relaxed, and smoother, more sedate migration. To determine which of these scenarios best represents the formation of our Solar system, we must turn to the structure of the system's small body populations, in which the scars of that migration are still clearly visible. We present the first results of a program investigating the effect of giant planet migration on the reservoirs of small bodies that existed at that time. As the planets migrate, they stir these reservoirs, scattering vast numbers of small bodies onto dynamically unstable orbits in the outer Solar system. The great majority of those bodies are rapidly removed from the system, through collisions and ejections, but a small number become captured as planetary Trojans or irregular satellites. Others are driven by the migration, leading to a significant sculpting of the asteroid belt and trans-Neptunian region. The capture and retention efficiencies to these stable reservoirs depend on the particular migration scenario used. Advocates of chaotic migration from an initially compact scenario argue that smoother, more sedate migration cannot explain the observed populations of Trojans and irregular satellites. Our results draw a strikingly different picture, revealing that such smooth migration is perfectly capable of reproducing the observed populations.
  • Jonathan Horner; F. Elliott Koch; Patryk Sofia Lykawka
    2013年02月 
    It is now accepted that the Solar system's youth was a dynamic and chaotic time. The giant planets migrated significant distances to reach their current locations, and evidence of that migration's influence on the Solar system abounds. That migration's pace, and the distance over which it occurred, is still heavily debated. Some models feature systems in which the giant planets were initially in an extremely compact configuration, in which Uranus and Neptune are chaotically scattered into the outer Solar system. Others feature architectures that were initially more relaxed, and smoother, more sedate migration. To determine which of these scenarios best represents the formation of our Solar system, we must turn to the structure of the system's small body populations, in which the scars of that migration are still clearly visible. We present the first results of a program investigating the effect of giant planet migration on the reservoirs of small bodies that existed at that time. As the planets migrate, they stir these reservoirs, scattering vast numbers of small bodies onto dynamically unstable orbits in the outer Solar system. The great majority of those bodies are rapidly removed from the system, through collisions and ejections, but a small number become captured as planetary Trojans or irregular satellites. Others are driven by the migration, leading to a significant sculpting of the asteroid belt and trans-Neptunian region. The capture and retention efficiencies to these stable reservoirs depend on the particular migration scenario used. Advocates of chaotic migration from an initially compact scenario argue that smoother, more sedate migration cannot explain the observed populations of Trojans and irregular satellites. Our results draw a strikingly different picture, revealing that such smooth migration is perfectly capable of reproducing the observed populations.
  • Lykawka, Patryk Sofia; Horner, Jonathan; Mueller, Thomas
    Japan Spaceguard Association, Spaceguard Research, Vol. 5, pp. 13-16 5 13 - 16 2013年 [査読有り]
  • Patryk Sofia Lykawka
    Monographs on environment, earth and planets MEEP 1 3 121 - 186 2012年12月 [査読有り]
     
    Trans-Neptunian objects (TNOs) are icy/rocky bodies that move beyond the orbit of Neptune in a region known as the trans-Neptunian belt (or Edgeworth-Kuiper belt). In contrast to the predictions of accretion models that feature protoplanetary disk planetesimals evolving on dynamically cold orbits (with both very small eccentricities, e, and inclinations, i), in reality TNOs exhibit surprisingly wide ranges of orbital eccentricities and inclinations. Several theoretical models have addressed the origin and orbital evolution of the main dynamical classes of TNOs, but none have successfully reproduced them all. In addition, none have explained several objects on peculiar orbits, or provided insightful predictions, without which a model cannot be tested properly against observations. Based on extensive simulations of planetesimal disks with the presence of the four giant planets and huge numbers of modeled planetesimals, I explore in detail the dynamics of the TNOs, in particular their (un)stable regions over timescales comparable to the age of the solar system, and the role of resonances across the entire trans-Neptunian region. I also propose that, along with the orbital history of the giant planets, the orbital evolution of primordial embryos (massive planetesimals comparable to Mars-Earth masses) can explain the fine orbital structure of the trans-Neptunian belt, the orbits of Jovian and Neptunian Trojans, and possibly the current orbits of the giant planets. Those primordial embryos were ultimately scattered by the giant planets, a process that stirred both the orbits of the giant planets and the primordial planetesimal disk to the levels observed at 40-50 AU. In particular, the main constraints provided by the trans-Neptunian belt are optimally satisfied if at least one such primordial embryo (planetoid) survived in the outskirts of the solar system.
  • Trans-Neptunian objects as natural probes to the unknown solar system（招待研究論文）
    パトリック ソフィア リカフィカ
    Monographs on Environment, Earth and Planets 1 121 - 186 2012年12月 
    Invited review paper （招待研究論文）
  • リカフィカ パトリック ソフィア; 伊藤 孝士
    日本惑星科学会秋期講演会予稿集 2012 83 - 83 日本惑星科学会 2012年10月
  • J. Horner; P. S. Lykawka
    Monthly Notices of the Royal Astronomical Society 426 1 159 - 166 2012年10月 [査読有り]
     
    We have performed a detailed dynamical study of the recently identified Neptunian Trojan 2004 KV 18, only the second object to be discovered librating around Neptune's trailing Lagrange point, L5. We find that 2004 KV 18 is moving on a highly unstable orbit, and was most likely captured from the Centaur population at some point in the last ∼1Myr, having originated in the scattered disc, beyond the orbit of Neptune. The instability of 2004 KV 18 is so great that many of the test particles studied leave the Neptunian Trojan cloud within just ∼0.1-0.3Myr, and it takes just 37Myr for half of the 91125 test particles created to study its dynamical behaviour to be removed from the Solar system entirely. Unlike the other Neptunian Trojans previously found to display dynamical instability on 100-Myr time-scales (2001 QR 322 and 2008 LC 18), 2004 KV 18 displays such extreme instability that it must be a temporarily captured Trojan, rather than a primordial member of the Neptunian Trojan population. As such, it offers a fascinating insight into the processes through which small bodies are transferred around the outer Solar system, and represents an exciting addition to the menagerie of the Solar system's small bodies. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
  • LYKAWKA Patryk Sofia; HORNER Jonathan
    日本天文学会年会講演予稿集 2012 108  2012年08月
  • NASA・OSS program（惑星系の起源研究プログラム）に投稿された研究計画申請等の審査報告書
    パトリック ソフィア リカフィカ
    2012年08月 
    計：8部
  • J. Horner; T. G. Müller; P. S. Lykawka
    Monthly Notices of the Royal Astronomical Society 423 3 2587 - 2596 Oxford University Press (OUP) 2012年07月 [査読有り]
     
    We have performed detailed thermophysical and dynamical modelling of the Jovian Trojan (1173) Anchises. Our results show that this is the most unusual object. By examining observational data of Anchises taken by IRAS, Akari and WISE at wavelengths between 11.5 and 60 μm, together with the variations in its optical light curve, we find that Anchises is most likely an elongated body, with an axis ratio, a/b, of around 1.4. This results in calculated best-fitting dimensions for Anchises of 170 × 121 × 121 km (or an equivalent diameter of 136 +18/-11 km). We find that the observations of Anchises are best fitted by the object having a retrograde sense of rotation, and an unusually high thermal inertia in the range 25-100Jm -2s -0.5K -1 (3σ confidence level). The geometric albedo of Anchises is found to be 0.027 (+0.006/-0.007). Anchises therefore has one of the highest published thermal inertias of any object larger than 100 km in diameter, at such large heliocentric distances, as well as being one of the lowest albedo objects ever observed. More observations (visual and thermal) are needed to see whether there is a link between the very shallow phase curve, with almost no opposition effect, and the derived thermal properties for this large Trojan asteroid. Our dynamical investigation of Anchises' orbit has revealed it to be dynamically unstable on time-scales of hundreds of millions of years, similar to the unstable Neptunian Trojans 2001 QR 322 and 2008LC 18. Unlike those objects, however, we find that the dynamical stability of Anchises is not a function of its initial orbital elements, the result of the exceptional precision with which its orbit is known. Our results are the first to show that a Jovian Trojan is dynamically unstable, and add further weight to the idea that the planetary Trojans likely represent a significant ongoing contribution to the dynamically unstable Centaur population, the parents of the short-period comets. The observed instability (fully half of all clones of Anchises escape the Solar system within 350Myr) does not rule out a primordial origin for Anchises, but, when taken in concert with the result of our thermophysical analysis, suggest that it would be a fascinating target for a future study. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
  • 平成23年度学内研究助成金・研究成果報告書
    パトリック ソフィア リカフィカ
    2012年06月
  • 平成23年度国立天文台共同研究報告書
    パトリック ソフィア リカフィカ
    2012年06月
  • Are Two of the Neptune Trojans Dynamically Unstable?
    Jonathan Horner; パトリック ソフィア リカフィカ
    Proceedings of the Australian Space Science Conference 11 27 - 38 2012年06月
  • J. Horner; P. S. Lykawka; M. T. Bannister; P. Francis
    Monthly Notices of the Royal Astronomical Society 422 3 2145 - 2151 2012年05月 [査読有り]
     
    The recent discovery of the first Neptune Trojan at the planet's trailing (L5) Lagrange point, 2008 LC18, offers an opportunity to confirm the formation mechanism of a member of this important tracer population for the Solar system's dynamical history. We tested the stability of 2008 LC18's orbit through a detailed dynamical study, using test particles spread across the ±3σ range of orbital uncertainties in a,e,i and Ω. This showed that the wide uncertainties of the published orbit span regions of both extreme dynamical instability, with lifetimes <100Myr, and significant stability, with lifetimes >1Gyr. The stability of 2008 LC18's clones is greatly dependent on their semimajor axis and only weakly correlated with their orbital eccentricity. Test particles on orbits with an initial semimajor axis of less than 29.91au have dynamical half-lives shorter than 100Myr; in contrast, particles with an initial semimajor axis of greater than 29.91au exhibit such strong dynamical stability that almost all are retained over the 1Gyr of our simulations. More observations of this object are necessary to improve the orbit. If 2008 LC18 is in the unstable region, then our simulations imply that it is either a temporary Trojan capture or a representative of a slowly decaying Trojan population (like its sibling the L4 Neptunian Trojan 2001 QR322), and that it may not be primordial. Alternatively, if the orbit falls into the larger, stable region, then 2008 LC18 is a primordial member of the highly stable and highly inclined component of the Neptune Trojan population, joining 2005 TN53 and 2007 VL305. We attempted to recover 2008 LC18 using the 2.3-m telescope at Siding Spring Observatory to provide this astrometry, but were unsuccessful due to the high stellar density of its current sky location near the Galactic centre. The recovery of this object will require a telescope in the 8-m class. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
  • Patryk Sofia Lykawka; Jonathan Horner; Tadashi Mukai; Akiko M. Nakamura
    Monthly Notices of the Royal Astronomical Society 421 2 1331 - 1350 Oxford University Press (OUP) 2012年04月 [査読有り]
     
    Recently, the first collisional family was identified in the trans-Neptunian belt (otherwise known as the Edgeworth-Kuiper belt), providing direct evidence of the importance of collisions between trans-Neptunian objects (TNOs). The family consists of the dwarf planet (136108) Haumea (formerly 2003 EL61), located at a semimajor axis, a, of ~43au, and at least 10 other ~100-km-sized TNOs located in the region a= 42-44.5 au. In this work, we model the long-term orbital evolution (4 Gyr) of an ensemble of fragments (particles) representing hypothetical post-collision distributions at the time of the family's birth based on our limited current understanding of the family's creation and of asteroidal collision physics. We consider three distinct scenarios, in which the kinetic energy of dispersed particles was varied such that their mean ejection velocities (v eje) were of the order of 200, 300 and 400 ms -1, respectively. Each simulation considered resulted in collisional families that reproduced that currently observed, despite the variation in the initial conditions modelled. The results suggest that 60-75 per cent of the fragments created in the collision will remain in the trans-Neptunian belt, even after 4 Gyr of dynamical evolution. The surviving particles were typically concentrated in wide regions of orbital element space centred on the initial impact location, with their orbits spread across a region spanning Δa~ 6-12 au, Δe~ 0.1-0.15 and Δi~ 7°-10°, with the exact range covered being proportional to v eje used in the model. Most of the survivors populated the so-called classical and detached regions of the trans-Neptunian belt, whilst a minor fraction either entered the scattered disc reservoir (<1 per cent) or were captured in Neptunian mean-motion resonances (<10 per cent). In addition, except for those fragments located near strong resonances (such as the 5:3 and 7:4), the great majority displayed negligible long-term orbital variation. This implies that the orbital distribution of the intrinsic Haumean family can be used to constrain the orbital conditions and physical nature of the collision that created the family, billions of years ago. Indeed, our results suggest that the formation of the Haumean collisional family most likely occurred after the bulk of Neptune's migration was complete, or even some time after the migration had completely ceased, although future work is needed to confirm this result. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
  • 平成23 年度国立天文台天文シミュレーションプロジェクト成果報告書
    パトリック ソフィア リカフィカ
    2012年04月 
    有無自己重力の微惑星円盤による惑星と小天体の軌道進化 Dynamical evolution of planets and small bodies in massive planetesimal disks with and without self-gravity
  • R. Brasser; M. E. Schwamb; P. S. Lykawka; R. S. Gomes
    Monthly Notices of the Royal Astronomical Society 420 4 3396 - 3402 2012年03月 [査読有り]
     
    We investigate the origin of three Centaurs with perihelia in the range 15-30 au, inclinations above 70° and semimajor axes shorter than 100 au. Based on long-term numerical simulations we conclude that these objects most likely originate from the Oort cloud rather than the Kuiper belt or scattered disc. We estimate that there are currently between 1 and 200 of these high-inclination, high-perihelion Centaurs with absolute magnitude H < 8. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
  • Jonathan Horner; Patryk Sofia Lykawka
    arXiv preprint arXiv:1202.5729 2012年02月 [査読有り]
     
    The Neptune Trojans are the most recently discovered population of small bodies in the Solar System. To date, only eight have been discovered, though it is thought likely that the total population at least rivals that of the asteroid belt. Their origin is still the subject of some debate. Here, we detail the results of dynamical studies of two Neptune Trojans, 2001 QR322 and 2008 LC18. We find that both objects lie very close to boundaries between dynamically stable and unstable regions, with a significant probability that either or both of the objects are actually unstable on timescales of a few hundred million years. Such instability supports the idea that at least these two Neptune Trojans are dynamically captured objects, rather than objects that formed in situ. This that does not, however, rule out the possibility that these two objects were captured during Neptune's proposed post-formation migration, and have remained as Trojans ever since.
  • Jonathan Horner; Patryk Sofia Lykawka
    2012年02月 
    The Neptune Trojans are the most recently discovered population of small bodies in the Solar System. To date, only eight have been discovered, though it is thought likely that the total population at least rivals that of the asteroid belt. Their origin is still the subject of some debate. Here, we detail the results of dynamical studies of two Neptune Trojans, 2001 QR322 and 2008 LC18. We find that both objects lie very close to boundaries between dynamically stable and unstable regions, with a significant probability that either or both of the objects are actually unstable on timescales of a few hundred million years. Such instability supports the idea that at least these two Neptune Trojans are dynamically captured objects, rather than objects that formed in situ. This that does not, however, rule out the possibility that these two objects were captured during Neptune's proposed post-formation migration, and have remained as Trojans ever since.
  • トロヤ群、ハウメア族、奇妙な小天体などによる主な結果と外部太陽系への含意 (特別講演)
    パトリック ソフィア リカフィカ
    2012年02月
  • Lykawka, Patryk Sofia
    arXiv preprint arXiv:1212.6124 2012年 [査読有り]
  • Lykawka, PS; Horner, J; Mukai, T; Nakamura, AM
    LPI Contributions 1667 6056 - 6056 2012年 [査読有り]
  • J. Horner; P. S. Lykawka
    Astronomy and Geophysics 52 4 4.24 - 4.30 2011年08月 [査読有り]
     
    Jonti Horner and Patryk Sofia Lykawka look at what the leftovers from planet formation reveal about the evolution of both the solar system and other planetary systems. © 2011 Royal Astronomical Society.
  • 平成22 年度国立天文台天文シミュレーションプロジェクト成果報告書
    パトリック ソフィア リカフィカ
    2011年04月 
    有無自己重力の微惑星円盤による惑星と小天体の軌道進化 Dynamical evolution of planets and small bodies in massive planetesimal disks with and without self-gravity
  • P. S. Lykawka; J. Horner; B. W. Jones; T. Mukai
    Monthly Notices of the Royal Astronomical Society 412 1 537 - 550 2011年03月 [査読有り]
     
    Following our earlier work studying the formation of the Neptunian Trojan population during the planet's migration, we present results examining the eventual fate of the Trojan clouds produced in that work. A large number of Trojans were followed under the gravitational influence of the giant planets for a period of at least 1Gyr. We find that the stability of Neptunian Trojans seems to be strongly correlated to their initial post-migration orbital elements, with those objects that survive as Trojans for billions of years, displaying negligible orbital evolution. The great majority of these survivors began the integrations with small eccentricities (e < 0.2) and small libration amplitudes (A < 30°-40°). The survival rate of 'pre-formed' Neptunian Trojans [which in general survived on dynamically cold orbits (e < 0.1,i < 5°-10°)] varied between ∼5 and 70percent, depending on the precise detail of their initial orbits. In contrast, the survival rate of 'captured' Trojans (on final orbits spread across a larger region of the e-i element space) was markedly lower, ranging between 1-10 per cent after 4 Gyr. Taken in concert with our earlier work and the broad i-distribution of the observed Trojan population, we note that planetary formation scenarios, which involve the slow migration (a few tens of millions of years) of Neptune from an initial planetary architecture that is both resonant and compact (aN < 18 au), provide the most promising fit of those we considered to the observed Trojan population. In such scenarios, we find that the present-day Trojan population would number ∼1 per cent of that which was present at the end of the planet's migration (i.e. survival rate of ∼1 per cent), with the bulk being sourced from captured, rather than pre-formed objects. We note, however, that even those scenarios still fail to reproduce the presently observed portion of the Neptune Trojan population moving on orbits with e < 0.1 but i > 20°. Dynamical integrations of the presently observed Trojans show that five out of the seven are dynamically stable on time-scales comparable to the age of the Solar system, while 2001 QR322 exhibits significant dynamical instability on time-scales of less than 1 Gyr. The seventh Trojan object, 2008 LC18, was only recently discovered and has such large orbital uncertainties that only future studies will be able to determine its stability. © 2010 The Authors Monthly Notices of the Royal Astronomical Society © 2010 RAS.
  • LYKAWKA Patryk Sofia; HORNER Jonathan; NAKAMURA Akiko M; MUKAI Tadashi
    日本天文学会年会講演予稿集 2011 97  2011年02月
  • LYKAWKA Patryk Sofia; HORNER Jonathan; JONES Barrie; MUKAI Tadashi
    日本天文学会年会講演予稿集 2011 96  2011年02月
  • Lykawka Patryk Sofia; o
    近畿大学学内研究助成金研究報告書 (2011.) 1  近畿大学 2011年 [査読有り]
  • Lykawka PS
    EPSC-DPS Joint Meeting 2011 1 1246  2011年 [査読有り]
  • Lykawka PS; Horner J; Nakamura AM; Mukai T
    EPSC-DPS Joint Meeting 2011 1 891  2011年 [査読有り]
  • F. Yoshida; Hsc Solar System Science Group; T. Terai; S. Urakawa; S. Abe; W. H. Ip; S. Takahashi; T. Ito; T. Ito
    Advances in Geosciences: Volume 25: Planetary Science (PS) 25 1 - 9 2011年01月 
    The Hyper Suprime-Cam (HSC) survey with the 8.2-m Subaru telescope is a multi-color photometric survey. The survey has been designed to provide a fundamental data set for various areas of cosmology-related researches in the next decade. However, it is also able to cover more general science purposes. In this paper, we describe briefly a current plan of the HSC survey and feasibility focusing on the Solar System science.
  • J. Horner; P. S. Lykawka
    International Journal of Astrobiology 9 4 227 - 234 Cambridge University Press (CUP) 2010年10月 [査読有り]
     
    AbstractOne of the key considerations when assessing the potential habitability of telluric worlds will be that of the impact regime experienced by the planet. In this work, we present a short review of our understanding of the impact regime experienced by the terrestrial planets within our own Solar system, describing the three populations of potentially hazardous objects which move on orbits that take them through the inner Solar system. Of these populations, the origins of two (the Near-Earth Asteroids and the Long-Period Comets) are well understood, with members originating in the Asteroid belt and Oort cloud, respectively. By contrast, the source of the third population, the Short-Period Comets, is still under debate. The proximate source of these objects is the Centaurs, a population of dynamically unstable objects that pass perihelion (closest approach to the Sun) between the orbits of Jupiter and Neptune. However, a variety of different origins have been suggested for the Centaur population. Here, we present evidence that at least a significant fraction of the Centaur population can be sourced from the planetary Trojan clouds, stable reservoirs of objects moving in 1:1 mean-motion resonance with the giant planets (primarily Jupiter and Neptune). Focussing on simulations of the Neptunian Trojan population, we show that an ongoing flux of objects should be leaving that region to move on orbits within the Centaur population. With conservative estimates of the flux from the Neptunian Trojan clouds, we show that their contribution to that population could be of order ~3%, while more realistic estimates suggest that the Neptune Trojans could even be the main source of fresh Centaurs. We suggest that further observational work is needed to constrain the contribution made by the Neptune Trojans to the ongoing flux of material to the inner Solar system, and believe that future studies of the habitability of exoplanetary systems should take care not to neglect the contribution of resonant objects (such as planetary Trojans) to the impact flux that could be experienced by potentially habitable worlds.
  • Our solar system and its members: the true character of a big family (公開講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2010年08月
  • Origin and Evolution of the Solar System: Evidence for a new planet in the solar system? (公開講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2010年08月
  • Trojan asteroids of Neptune and their link with comets in the solar system (研究紹介)
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    'New Scientist' and online at 'Universe Today' and 'Space.com' 2010年07月
  • J. Horner; P. S. Lykawka
    Monthly Notices of the Royal Astronomical Society 405 1 49 - 56 2010年06月 [査読有り]
     
    Since early work on the stability of the first Neptunian Trojan, 2001 QR322, suggested that it was a dynamically stable, primordial body, it has been assumed that this applies to both that object and its more recently discovered brethren. However, it seems that things are no longer so clear-cut. In this work, we present the results of detailed dynamical simulations of the orbital behaviour of 2001 QR322. Using an ephemeris for the object that has significantly improved since earlier works, we follow the evolution of 19 683 test particles, placed on orbits within the observational error ellipse of 2001 QR322's orbit, for a period of 1 Gyr. We find that majority of these 'clones' of 2001 QR322 are dynamically unstable, exhibiting a near-exponential decay from both the Neptunian Trojan cloud (decay half-life of ∼550 Myr) and the Solar system (decay half-life of ∼590 Myr). The stability of the object within Neptune's Trojan cloud is found to be strongly dependent on the initial semimajor axis used, with these objects located at a ≥ 30.30 au being significantly less stable than those interior to this value, as a result of their having initial libration amplitudes very close to a critical threshold dividing regular and irregular motion, located at ∼70°-75° (full extent of angular motion). This result suggests that if 2001 QR322 is a primordial Neptunian Trojan, it must be a representative of a population that was once significantly larger than that we see today and adds weight to the idea that the Neptune Trojans may represent a significant source of objects moving on unstable orbits between the giant planets (the Centaurs). © 2010 The Authors. Journal compilation © 2010 RAS.
  • P. S. Lykawka; J. Horner
    Monthly Notices of the Royal Astronomical Society 405 2 1375 - 1383 Oxford University Press (OUP) 2010年06月 [査読有り]
     
    Of the four giant planets in the Solar system, only Jupiter and Neptune are currently known to possess swarms of Trojan asteroids - small objects that experience a 1:1 mean motion resonance with their host planet. In Lykawka et al., we performed extensive dynamical simulations, including planetary migration, to investigate the origin of the Neptunian Trojan population. Utilizing the vast amount of simulation data obtained for that work, together with fresh results from new simulations, we here investigate the dynamical capture of Trojans by all four giant planets from a primordial trans-Neptunian disc. We find the likelihood of a given planetesimal from this region being captured on to an orbit within Jupiter's Trojan cloud lies between several times 10-6 and 10-5. For Saturn, the probability is found to be in the range <10-6 to 10-5, whilst for Uranus the probabilities range between 10-5 and 10-4. Finally, Neptune displays the greatest probability of Trojan capture, with values ranging between 10-4 and 10-3. Our results suggest that all four giant planets are able to capture and retain a significant population of Trojan objects from the disc by the end of planetary migration. As a result of encounters with the giant planets prior to Trojan capture, these objects tend to be captured on orbits that are spread over a wide range of orbital eccentricities and inclinations. The bulk of captured objects are to some extent dynamically unstable, and therefore, the populations of these objects tend to decay over the age of the Solar system, providing an important ongoing source of new objects moving on dynamically unstable orbits among the giant planets. Given that a huge population of objects would be displaced by Neptune's outward migration (with a potential cumulative mass a number of times that of the Earth), we conclude that the surviving remnant of the Trojans captured during the migration of the outer planets might be sufficient to explain the currently known Trojan populations in the outer Solar system. © 2010 The Authors. Journal compilation © 2010 RAS.
  • P. S. Lykawka; J. Horner; B. W. Jones; T. Mukai
    Monthly Notices of the Royal Astronomical Society 404 3 1272 - 1280 2010年05月 [査読有り]
     
    Current models of Solar system formation suggest that the four giant planets accreted as a significantly more compact system than we observe today. In this work, we investigate the dynamical stability of pre-formed Neptune Trojans under the gravitational influence of the four giant planets in compact planetary architectures, over 10 Myr. In our modelling, the initial orbital locations of Uranus and Neptune (aN) were varied to produce systems in which those planets moved on non-resonant orbits or in which they lay in their mutual 1:2, 2:3 and 3:4 mean-motion resonances (MMRs). In total, 420 simulations were carried out, examining 42 different architectures, with a total of 840 000 particles across all runs. In the non-resonant cases, the Trojans suffered only moderate levels of dynamical erosion, with the most compact systems (those with aN≤ 18 au) losing around 50 per cent of their Trojans by the end of the integrations. In the 2:3 and 3:4 MMR scenarios, however, dynamical erosion was much higher with depletion rates typically greater than 66 per cent and total depletion in the most compact systems. The 1:2 resonant scenarios featured disruption on levels intermediate between the non-resonant cases and other resonant scenarios, with depletion rates of the order of tens of per cent. Overall, the great majority of plausible pre-migration planetary architectures resulted in severe levels of depletion of the Neptunian Trojan clouds. In particular, if Uranus and Neptune formed near their mutual 2:3 or 3:4 MMR and at heliocentric distances within 18 au (as favoured by recent studies), we found that the great majority of pre-formed Trojans would have been lost prior to Neptune's migration. This strengthens the case for the great bulk of the current Neptunian Trojan population having been captured during that migration. © 2010 The Authors. Journal compilation © 2010 RAS.
  • 平成21 年度国立天文台天文シミュレーションプロジェクト成果報告書
    パトリック ソフィア リカフィカ
    2010年04月 
    有無自己重力の微惑星円盤による惑星と小天体の軌道進化 Dynamical evolution of planets and small bodies in massive planetesimal disks with and without self-gravity
  • J. Horner; P. S. Lykawka
    Monthly Notices of the Royal Astronomical Society 402 1 13 - 20 Oxford University Press (OUP) 2010年02月 [査読有り]
     
    The fact that the Centaurs are the primary source of the short-period comets is well established. However, the origin of the Centaurs themselves is still under some debate, with a variety of different source reservoirs being proposed in the last decade. In this work, we suggest that the Neptune Trojans (together with the Jovian Trojans) could represent an additional significant source of Centaurs. Using dynamical simulations of the first Neptune Trojan discovered (2001 QR322), together with integrations following the evolution of clouds of theoretical Neptune Trojans obtained during simulations of planetary migration, we show that the Neptune Trojan population contains a great number of objects which are unstable on both Myr and Gyr time-scales. Using individual examples, we show how objects that leave the Neptunian Trojan cloud evolve on to orbits indistinguishable from those of the known Centaurs, before providing a range of estimates of the flux from this region to the Centaur population. With only moderate assumptions, it is shown that the Trojans can contribute a significant proportion of the Centaur population, and may even be the dominant source reservoir. This result is supported by past work on the colours of the Trojans and the Centaurs, but it will take future observations to determine the full scale of the contribution of the escaped Trojans to the Centaur population. © 2010 The Authors. Journal compilation © 2010 RAS.
  • Lykawka Patryk S; Horner Jonathan; Jones Barrie; Mukai Tadashi
    Bulletin of the American Astronomical Society 42 1001  2010年 [査読有り]
  • 惑星科学（新惑星理論を含む）：社会への影響とニセ科学との違い
    パトリック ソフィア リカフィカ; Tadashi Mukai
    2009年12月 
    SBS TV channel (Korea)
  • P. S. Lykawka; J. Horner; B. W. Jones; T. Mukai
    Monthly Notices of the Royal Astronomical Society 398 4 1715 - 1729 2009年10月 [査読有り]
     
    We present the results of detailed dynamical simulations of the effect of the migration of the four giant planets on both the transport of pre-formed Neptune Trojans and the capture of new Trojans from a trans-Neptunian disc. The cloud of pre-formed Trojans consisted of thousands of massless particles placed on dynamically cold orbits around Neptune's L4 and L5 Lagrange points, while the trans-Neptunian disc contained tens of thousands of such particles spread on dynamically cold orbits between the initial and final locations of Neptune. Through the comparison of the results with the previous work on the known Neptunian Trojans, we find that scenarios involving the slow migration of Neptune over a large distance (50 Myr to migrate from 18.1 au to its current location, using an exponential-folding time of τ = 10 Myr) provide the best match to the properties of the known Trojans. Scenarios with faster migration (5 Myr, with τ = 1 Myr), and those in which Neptune migrates from 23.1 au to its current location, fail to adequately reproduce the current-day Trojan population. Scenarios which avoid disruptive perturbation events between Uranus and Neptune fail to yield any significant excitation of pre-formed Trojans (transported with efficiencies between 30 and 98 per cent whilst maintaining the dynamically cold nature of these objects - e < 0.1, i < 5°). Conversely, scenarios with periods of strong Uranus-Neptune perturbation lead to the almost complete loss of such pre-formed objects. In these cases, a small fraction (∼0.15 per cent) of these escaped objects are later recaptured as Trojans prior to the end of migration, with a wide range of eccentricities (<0.35) and inclinations (<40°). In all scenarios (including those with such disruptive interaction between Uranus and Neptune), the capture of objects from the trans-Neptunian disc (through which Neptune migrates) is achieved with efficiencies between ∼0.1 and ∼1 per cent. The captured Trojans display a wide range of inclinations (<40° for slow migration, and <20° for rapid migration) and eccentricities (<0.35), and we conclude that, given the vast amount of material which undoubtedly formed beyond the orbit of Neptune, such captured objects may be sufficient to explain the entire Neptune Trojan population. © 2009 RAS.
  • The possible existence of a new planet in the solar system! (公開講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2009年07月
  • 大和日英基金財団の共同研究助成金・研究実績報告書
    Jonathan Horner; パトリック ソフィア リカフィカ
    Research Report Research Report 2009年06月 
    Research Report for the Daiwa Foundation Small Grant for research collaboration with Dr. Jonathan Horner (PI), Open University, United Kingdom. (2008年7月?2009年6月)
  • グレイトブリテン・ササカワ財団の共同研究助成金・研究実績報告書
    Jonathan Horner; パトリック ソフィア リカフィカ
    Research Report Research Report 2009年06月 
    Great Britain Sasakawa Foundation Small Grant for research collaboration with Dr. Jonathan Horner (PI), Open University, United Kingdom. (2008年7月-2009年6月)
  • 太陽系と外縁天体の起源と進化
    パトリック ソフィア リカフィカ
    2009年05月
  • 日本学術振興会の研究助成金・研究実績報告書
    Tadashi Mukai; パトリック ソフィア リカフィカ
    Research Report Research Report 2009年04月 
    平成２０年度科学研究費補助金実績報告書 (研究員・研究分担者)
  • 平成20 年度国立天文台天文シミュレーションプロジェクト成果報告書
    パトリック ソフィア リカフィカ
    2009年04月 
    1.カイパーベルト天体の衝突と数十億年間の軌道進化 2.巨大微惑星の存在による太陽系小天体と巨大惑星の軌道進化 1. Collisional families in the Kuiper belt and their long-term dynamical evolution 2. Dynamical Evolution of Giant Planets and Solar System Small Bodies with the Presence of Embedded Massive Planetesimals
  • Patryk Sofia Lykawka; Tadashi Mukai
    Advances in Geosciences: Volume 15: Planetary Science (PS) 15 293 - 304 2009年01月 [査読有り]
     
    © 2009 World Scientific Publishing Company. All rights reserved. Trans-Neptunian objects (TNOs) orbiting in the Edgeworth–Kuiper Belt carry precious information about the origin and evolution of the Solar System. 1–5 The Kuiper Belt has a very complex orbital structure. Indeed, TNOs exhibit surprisingly large eccentricities, e, and inclinations, i, and are classified in distinct dynamical classes. 2,4,6 Here, we propose that the Kuiper Belt orbital structure can be explained by a massive scattered planetesimal with tenths of the Earth’s mass, which later remained in the system in a distant stable orbit (an outer planet). Near the end of planet formation, the outer planet was firstly scattered by one of the icy giant planets; then it dynamically excited the primordial planetesimal disk over at least tens of Myr, reproducing the levels observed at 40–50AU and the truncation of the disk at about 48AU before planet migration. Later, the outer planet was captured by a distant resonance with Neptune of the type r:1 or r:2 (e.g., 6:1, 7:1,…), acquiring an inclined stable orbit (≥100AU; 20°–40°), thus preserving the Kuiper Belt over ~4Gyr. Our model explains the following: (1) Depletion of the inner Kuiper Belt; (2) The entire currently known resonant populations in the Kuiper Belt, including Neptune Trojans and resonant TNOs in distant resonances (>50AU); (3) Formation of scattered and detached TNOs, including analogues of (136199) Eris, 2004 XR190, (148209) 2000 CR105, and (90377) Sedna; (4) Classical TNOs and their dual nature of cold and hot populations; (5) Orbital excitation of classical TNOs; (6) The Kuiper Belt outer edge at about 48AU; (7) Loss of ~99% of the initial total mass of the Kuiper Belt through dynamical depletion and enhanced collisional grinding; (8) Neptune’s current orbit at 30.1AU. In summary, our scenario consistently reproduces all main aspects of Kuiper Belt architecture with unprecedented detail. The best constraints obtained from the model for the outer planet are: aP = 100–175AU (currently near or inside an r:1 or r:2 resonance), qP >80AU, iP = 20 ° –40°, and apparent magnitude mP ~15–17mag at perihelion (assuming an albedo of 0.1–0.3 and qP = 80–90AU).
  • Origin and Dynamical Evolution of Planets and Minor Bodies in the Solar System (特別講演) [in English]
    パトリック ソフィア リカフィカ
    2008年12月
  • Lykawka Patryk Sofia; 向井 正
    日本惑星科学会秋期講演会予稿集 2008 0 101 - 101 日本惑星科学会 2008年11月
  • Lykawka Patryk Sofia; Horner Jonathan; Mukai Tadashi; Jones Barrie
    日本惑星科学会秋期講演会予稿集 2008 0 71 - 71 日本惑星科学会 2008年11月
  • Life as a Foreign Researcher and Outstanding Questions about Planetary Sciences (公開講演) [in English]
    パトリック ソフィア リカフィカ
    2008年10月
  • 向井 正; Lykawka Patryk Sofia
    科学 78 9 985 - 989 岩波書店 2008年09月
  • パトリック ソフィア リカフィカ; Tadashi Mukai
    2008年07月 
    太陽系・カイパーベルト科学と太陽系外部に未知の惑星の理論は大きな反響をよび、太陽系内にある特異な天体や遠方にある未知の惑星への国内外の天文学者の観測意欲を高めました。また、惑星科学や天文学に関する多くのトピックがマスコミで紹介されました（日本を始め、〜58カ国で科学雑誌や新聞など100以上の項目・記事）。
  • パトリック ソフィア リカフィカ; Tadashi Mukai
    2008年06月 
    SCIENCE ZERO (2回 in June/2008)
  • パトリック ソフィア リカフィカ; 大朝 由美子
    天文ガイド 135 2008年05月
  • Origin and Evolution of the Solar System (公開講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2008年05月
  • Patryk S. Lykawka; Tadashi Mukai
    The Astronomical Journal 135 4 1161 - 1200 American Astronomical Society 2008年04月 [査読有り]
     
    Trans-Neptunian objects (TNOs) are remnants of a collisionally and dynamically evolved planetesimal disk in the outer solar system. This complex structure, known as the trans-Neptunian belt (or Edgeworth-Kuiper belt), can reveal important clues about disk properties, planet formation, and other evolutionary processes. In contrast to the predictions of accretion theory, TNOs exhibit surprisingly large eccentricities, e, and inclinations, i, which can be grouped into distinct dynamical classes. Several models have addressed the origin and orbital evolution of TNOs, but none has reproduced detailed observations, e.g., all dynamical classes and peculiar objects, or provided insightful predictions. Based on extensive simulations of planetesimal disks with the presence of the four giant planets and massive planetesimals, we propose that the orbital history of an outer planet with tenths of the Earth's mass can explain the trans-Neptunian belt orbital structure. This massive body was likely scattered by one of the giant planets, which then stirred the primordial planetesimal disk to the levels observed at 40-50 AU and truncated it at about 48 AU before planet migration. The outer planet later acquired an inclined stable orbit (≥100 AU; 20-40°) because of a resonant interaction with Neptune (an r:1 or r:2 resonance possibly coupled with the Kozai mechanism), guaranteeing the stability of the trans-Neptunian belt. Our model consistently reproduces the main features of each dynamical class with unprecedented detail; it also satisfies other constraints such as the current small total mass of the trans-Neptunian belt and Neptune's current orbit at 30.1 AU. We also provide observationally testable predictions. © 2008. The American Astronomical Society. All rights reserved.
  • Origin and Evolution of the Solar System (公開講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2008年04月
  • Origin and Dynamical structure of the Trans-Neptunian Belt: Evidence for an Outer Planet in the Solar System? (特別講演) [in English]
    パトリック ソフィア リカフィカ
    2008年03月
  • Origin and Dynamical Structure of the Trans-Neptunian Belt: Evidence for an Outer Planet in the Solar System (研究報告講演)
    パトリック ソフィア リカフィカ; Tadashi Mukai
    2008年03月
  • パトリック ソフィア リカフィカ; Tadashi Mukai
    2008年02月
  • Lykawka Patryk Sofia; 向井正
    日本惑星科学会秋期講演会予稿集 2008 101 - 101 日本惑星科学会 2008年 [査読有り]
  • Lykawka, PS; Mukai, T
    LPI Contributions 1405 8231 - 8231 2008年 [査読有り]
  • Lykawka, PS; Mukai, T
    LPI Contributions 1405 8234 - 8234 2008年 [査読有り]
  • Michikami T; Miura S; Haruyama J; Lykawka PS
    Lunar and Planetary Science Conference 39 1593  2008年 [査読有り]
  • Lykawka Patryk Sofia; Horner Jonathan; Mukai Tadashi; Jones Barrie
    日本惑星科学会秋期講演会予稿集 2008 71 - 71 日本惑星科学会 2008年 [査読有り]
  • Origin and Dynamical structure of the Trans-Neptunian Belt (招待講演) [in English]
    パトリック ソフィア リカフィカ
    2008年
  • LYKAWKA Patryk Sofia; HORNER Jonathan; MUKAI Tadashi; JONES Barrie
    日本惑星科学会秋季講演会予稿集 2008 71  2008年 [査読有り]
  • LYKAWKA Patryk Sofia; MUKAI Tadashi
    日本惑星科学会秋季講演会予稿集 2008 101  2008年
  • 向井 正; リカフィカ パトリック ソフィア
    日本流体力学会年会講演論文集 2008 17 - 22 日本流体力学会 2008年 
    We present an introduction of "New Planet Hypothesis" in our solar system. This idea comes from the fact that the trans-Neptunian Objects (TNOs), discovered in 1992 and found, up to now, almost 1200 objects, show unexpected orbital features. Our "new planet" could excite the original static orbits of TNOs by its gravitational effect during its dynamical evolution, and consequently such unexpected features of TNOs' orbits appeared.
  • 向井 正; リカフイカ パトリックソフィア
    日本流体力学会誌「ながれ」 27 6 425 - 430 社団法人 日本流体力学会 2008年 [査読有り]
     
    本稿は2008年9月6日に神戸大学で行なわれた「2008年度流体力学会年会」での特別講演「新惑星仮説の誕生」に一部修正を加えた解説である.
  • 向井 正; リカフイカ パトリックソフィア
    日本流体力学会誌「ながれ」 27 6 425 - 430 The Japan Society of Fluid Mechanics 2008年 [査読有り]
     
    本稿は2008年9月6日に神戸大学で行なわれた「2008年度流体力学会年会」での特別講演「新惑星仮説の誕生」に一部修正を加えた解説である.
  • Patryk Sofia Lykawka; Tadashi Mukai
    Icarus 192 1 238 - 247 Elsevier BV 2007年12月 [査読有り]
     
    We investigate the dynamical evolution of trans-neptunian objects (TNOs) in typical scattered disk orbits (scattered TNOs) by performing simulations using several thousand particles lying initially on Neptune-encountering orbits. We explore the role of resonance sticking in the scattered disk, a phenomenon characterized by multiple temporary resonance captures ('resonances' refers to external mean motion resonances with Neptune, which can be described in the form r : s, where the arguments r and s are integers). First, all scattered TNOs evolve through intermittent temporary resonance capture events and gravitational scattering by Neptune. Each scattered TNO experiences tens to hundreds of resonance captures over a period of 4 Gyr, which represents about 38% of the object's lifetime (mean value). Second, resonance sticking plays an important role at semimajor axes a < 250 AU, where the great majority of such captures occurred. It is noteworthy that the stickiest (i.e., dominant) resonances in the scattered disk are located within this distance range and are those possessing the lowest argument s. This was evinced by r : 1, r : 2 and r : 3 resonances, which played the greatest role during resonance sticking evolution, often leading to captures in several of their neighboring resonances. Finally, the timescales and likelihood of temporary resonance captures are roughly proportional to resonance strength. The dominance of low s resonances is also related to the latter. In sum, resonance sticking has an important impact on the evolution of scattered TNOs, contributing significantly to the longevity of these objects. © 2007 Elsevier Inc. All rights reserved.
  • Origin and Evolution of the Solar System: Outstanding Questions and Mysteries (公開講演) [in English]
    パトリック ソフィア リカフィカ
    2007年12月
  • A distant planet beyond Pluto and the origin of Edgeworth-Kuiper Belt architecture (特別講演) [in English]
    パトリック ソフィア リカフィカ
    2007年09月
  • Patryk Sofia Lykawka; Tadashi Mukai
    Icarus 189 1 213 - 232 Elsevier BV 2007年07月 [査読有り]
     
    The orbital structure of trans-neptunian objects (TNOs) in the trans-neptunian belt (Edgeworth-Kuiper belt) and scattered disk provides important clues to understand the origin and evolution of the Solar System. To better characterize these populations, we performed computer simulations of currently observed objects using long-arc orbits and several thousands of clones. Our preliminary analysis identified 622 TNOs, and 65 non-resonant objects whose orbits penetrate that of at least one of the giant planets within 1 Myr (the centaurs). In addition, we identified 196 TNOs locked in resonances with Neptune, which, sorted by distance from the Sun, are 1:1 (Neptune trojans), 5:4, 4:3, 11:8, 3:2, 18:11, 5:3, 12:7, 19:11, 7:4, 9:5, 11:6, 2:1, 9:4, 16:7, 7:3, 12:5, 5:2, 8:3, 3:1, 4:1, 11:2, and 27:4. Kozai resonant TNOs are found inside the 3:2, 5:3, 7:4, and 2:1 resonances. We present detailed general features for the resonant populations (i.e., libration amplitude angles, libration centers, Kozai libration amplitudes, etc.). Taking together the simulations of Lykawka and Mukai [Lykawka, P.S., Mukai, T., 2007. Icarus 186, 331-341], an improved classification scheme is presented revealing five main classes: centaurs, resonant, scattered, detached and classical TNOs. Scattered and detached TNOs (non-resonant) have q (perihelion distance) <37 AU and q > 40  AU, respectively. TNOs with 37  AU < q < 40  AU occupy an intermediate region where both classes coexist. Thus, there are no clear boundaries between the scattered and detached regions. We also securely identified a total of 9 detached TNOs by using 4-5 Gyr orbital integrations. Classical objects are non-resonant TNOs usually divided into cold and hot populations. Their boundaries are as follows: cold classical TNOs (i ≤ 5 °) are located at 37  AU < a < 40  AU (q > 37  AU) and 42  AU < a < 47.5  AU (q > 38  AU), and hot classical TNOs (i > 5 °) occupy orbits with 37  AU < a < 47.5  AU (q > 37  AU). However, a more firm classification is found with i > 10 ° for hot classical TNOs. Lastly, we discuss some implications of our classification scheme comparing all TNOs with our model and other past models. © 2007 Elsevier Inc. All rights reserved.
  • Solar system topics (ゲスト講義) [in English]
    パトリック ソフィア リカフィカ
    2007年05月
  • 向井 正; Lykawka Patryk Sofia
    科学 77 2 171 - 176 岩波書店 2007年02月
  • Patryk Sofia Lykawka; Tadashi Mukai
    Icarus 186 2 331 - 341 Elsevier BV 2007年02月 [査読有り]
     
    Resonance occupation of trans-neptunian objects (TNOs) in the scattered disk (> 48   AU) was investigated by integrating the orbits of 85 observed members for 4 Gyr. Twenty seven TNOs were locked in the 9:4, 16:7, 7:3, 12:5, 5:2, 8:3, 3:1, 4:1, 11:2, and 27:4 resonances. We then explored mechanisms for the origin of the resonant structure in the scattered disk, in particular the long-term 9:4, 5:2, and 8:3 resonant TNOs (median 4 Gyr), by performing large scale simulations involving Neptune scattering and planetary migration over an initially excited planetesimals disk (wide range of eccentricities and inclinations). To explain the formation of Gyr-resident populations in such distant resonances, our results suggest the existence of a primordial planetesimal disk of at least 45-50 AU radius that suffered a dynamical perturbation leading to 0.1-0.3 or greater eccentricities and a range of inclinations up to ∼20° during early stages of the Solar System history, before planetary migration. © 2006 Elsevier Inc. All rights reserved.
  • Sofia Lykawka P; Mukai T
    European Planetary Science Congress 2007 1 874  2007年 [査読有り]
  • ソフィア リカフィカ パトリック
    日本惑星科学会秋季講演会予稿集 2007 0 113 - 113 日本惑星科学会 2007年 [査読有り]
     
    Trans-Neptunian objects (TNOs) orbit beyond Neptune and offer important clues on the origin and evolution of the solar system. We investigated the dynamical properties of 622 TNOs by performing computer simulations of their orbits plus several clones. We identified 196 TNOs locked in resonance with Neptune in the Edgeworth-Kuiper belt. Occupied resonances sorted by distance from the Sun are: 1:1, 5:4, 4:3, 11:8, 3:2, 18:11, 5:3, 12:7, 19:11, 7:4, 9:5, 11:6, 2:1, 9:4, 16:7, 7:3, 12:5, 5:2, 8:3, 3:1, 4:1, 11:2, and 27:4. Beyond 50AU, we examined the long-term evolution of 27 resonant TNOs by integrating their orbits over 4Gyr. The origin of 4Gyr-resident 9:4, 5:2, and 8:3 resonant TNOs was investigated using static and planetary migration dynamical models. We found that the long-term stable populations of 9:4, 5:2, and 8:3 resonant TNOs are well explained through adiabatic resonance capture by a migrating Neptune over a dynamically excited ancient trans-Neptunian belt. Therefore, this suggests that the primordial planetesimal disk had at least 47-50AU in radius, and suffered a dynamical perturbation leading to 0.1-0.3 or greater eccentricities and a range of inclinations up to ~20 degrees during early stages of the solar system's existence, before planetary migration.
  • Sofia Lykawka P; Mukai T
    European Planetary Science Congress 2007 1 847  2007年 [査読有り]
  • Lykawka Patryk S; Mukai T
    Bulletin of the American Astronomical Society 39 1042  2007年 [査読有り]
  • LYKAWKA Patryk Sofia; MUKAI Tadashi
    日本惑星科学会秋季講演会予稿集 2007 39  2007年
  • ソフィア リカフィカ パトリック
    日本惑星科学会秋季講演会予稿集 2007 0 39 - 39 日本惑星科学会 2007年 [査読有り]
     
    Trans-Neptunian objects (TNOs) orbit in the so called trans-Neptunian belt (or Edgeworth-Kuiper belt). These icy bodies represent the relics of planet accretion in the outer solar system. We investigated the structure of the trans-Neptunian belt by conducting extensive computer simulations (4-5Gyr) using tens of thousands of particles in planetesimal disks. After taking into account several observational constraints, we developed a model to explain the origin and evolution of the belt by considering a hypothetical outer planet (or planetoid) with tenths of Earth masses orbiting beyond about 100AU.An outer planet in a distant orbit in the scattered disk can explain the ancient trans-Neptunian belt excitation, the formation of an outer edge at ~48AU, the entire TNO resonant population, the formation of detached TNOs and many other features in a self-consistent way. Noteworthy, the results match very well up-to-date observations. The best constraints obtained from the model for the planetoid are: aP=100-170AU, qP>80AU, iP=30-50 degrees, albedo=0.1-0.3, and apparent magnitude mP=15~17mag at perihelion.In summary, our model with the existence of a distant massive planet successfully describes the trans-Neptunian belt architecture with an unprecedented level of details.
  • 優秀ポスター賞
    パトリック ソフィア リカフィカ
    2006年12月 
    Poster presentation: "Trans-Neptunian Region Architecture: Evidence for a Planet Beyond Pluto"
  • Lykawka Patryk Sofia; Mukai Tadashi
    Planetary and Space Science 54 1 87 - 100 Pergamon 2006年01月 [査読有り]
     
    In our preliminary study, we have investigated basic properties and dynamical evolution of classical TNOs around the 7:4 mean motion resonance with Neptune (a?43.7 AU), motivated by observational evidences that apparently present irregular features near this resonance (see [Lykawka and Mukai, 2005a. Exploring the 7:4 mean motion resonance - I. Dynamical evolution of classical trans-Neptunian objects (TNOs). Space Planet. Sci. 53, 1175-1187]; hereafter "Paper I"). In this paper, we aim to explore the dynamical long-term evolution in the scattered disk (but not its early formation) based on the computer simulations performed in Paper I together with extra computations. Specifically, we integrated the orbital motion of test particles (totalizing a bit more than 10,000) placed around the 7:4 mean motion resonance under the effect of the four giant planets for the age of the Solar System. In order to investigate chaotic diffusion, we also conducted a special simulation with on-line computation of proper elements following tracks in phase space over 4-5 Gyr. We found that: (1) A few percent (1-2%) of the test particles survived in the scattered disk with direct influence of other Neptunian mean motion resonances, indicating that resonance sticking is an extremely common phenomenon and that it helps to enhance scattered objects longevity. (2) In the same region, the so-called extended scattered TNOs are able to form via very long resonance trapping under certain conditions. Namely, if the body spends more than about 80% of its dynamical lifetime trapped in mean motion resonance(s) and there is the action of a k+1 or (k+2)/2 mean motion resonance (e.g., external mean motion resonances with Neptune described as (j+k)/j with j=1 and 2, respectively). According to this hypothetical mechanism, 5-15% of current scattered TNOs would possess q>40AU thus probably constituting a significant part of the extended scattered disk. (3) Moreover, considering hot orbital initial conditions, it is likely that the trans-Neptunian belt (or Edgeworth-Kuiper belt) has been providing members to the scattered disk, so that scattered TNOs observed today would consist of primordial scattered bodies mixed with TNOs that came from unstable regions of the trans-Neptunian belt in the past. Considering the three points together, our results demonstrated that the scattered disk has been evolving continuously since early times until present. ? 2005 Elsevier Ltd. All rights reserved.
  • Lykawka PS; Mukai T
    AGU Fall Meeting Abstracts 1 0178  2006年 [査読有り]
  • 専門分野で分析用様々なデータ検出するコンピューターコード(RESTICK)
    パトリック ソフィア リカフィカ
    Used to extract the results in many scientific publications 2006年
  • Patryk Sofia Lykawka; Tadashi Mukai
    Planetary and Space Science 53 13 1319 - 1330 2005年11月 [査読有り]
     
    Transneptunian objects (TNOs) orbit beyond Neptune and do offer important clues about the formation of our solar system. Although observations have been increasing the number of discovered TNOs and improving their orbital elements, very little is known about elementary physical properties such as sizes, albedos and compositions. Due to TNOs large distances (>40 AU) and observational limitations, reliable physical information can be obtained only from brighter objects (supposedly larger bodies). According to size and albedo measurements available, it is evident the traditionally assumed albedo p=0.04 cannot hold for all TNOs, especially those with approximately absolute magnitudes H≤5.5. That is, the largest TNOs possess higher albedos (generally > 0.04) that strongly appear to increase as a function of size. Using a compilation of published data, we derived empirical relations which can provide estimations of diameters and albedos as a function of absolute magnitude. Calculations result in more accurate size/albedo estimations for TNOs with H≤5.5 than just assuming p=0.04. Nevertheless, considering low statistics, the value p=0.04 sounds still convenient for H>5.5 non-binary TNOs as a group. We also discuss about physical processes (e.g., collisions, intrinsic activity and the presence of tenuous atmospheres) responsible for the increase of albedo among large bodies. Currently, all big TNOs (>700 km) would be capable to sustain thin atmospheres or icy frosts composed of CH 4, CO or N2 even for body bulk densities as low as 0.5 g cm-3. A size-dependent albedo has important consequences for the TNOs size distribution, cumulative luminosity function and total mass estimations. According to our analysis, the latter can be reduced up to 50% if higher albedos are common among large bodies. Lastly, by analyzing orbital properties of classical TNOs (42AU99.63% confidence level. Furthermore, more massive classical bodies are anomalously present at a<43.5AU, a result statistically significant and apparently not caused by observational biases. This feature would provide a new constraint for transneptunian belt formation models. © 2005 Elsevier Ltd. All rights reserved.
  • Patryk Sofia Lykawka; Tadashi Mukai
    Earth, Moon, and Planets 97 1-2 107 - 126 Springer Science and Business Media LLC 2005年10月 [査読有り]
     
    Classical trans-Neptunian objects (TNOs) are believed to represent the most dynamically pristine population in the trans-Neptunian belt (TNB) offering unprecedented clues about the formation of our Solar System. The long term dynamical evolution of classical TNOs was investigated using extensive simulations. We followed the evolution of more than 17000 particles with a wide range of initial conditions taking into account the perturbations from the four giant planets for 4 Gyr. The evolution of objects in the classical region is dependent on both their inclination and semimajor axes, with the inner (a < 45 AU) and outer regions (a > 45 AU) evolving differently. The reason is the influence of overlapping secular resonances with Uranus and Neptune (40-42 AU) and the 5:3 (a-42.3 AU), 7:4 (a-43.7 AU), 9:5 (a-44.5 AU) and 11:6 (a-45.0 AU) mean motion resonances strongly sculpting the inner region, while in the outer region only the 2:1 mean motion resonance (a-47.7 AU) causes important perturbations. In particular, we found: (a) A substantial erosion of low-i bodies (i < 10°) in the inner region caused by the secular resonances, except those objects that remained protected inside mean motion resonances which survived for billion of years; (b) An optimal stable region located at 45 AU 40 AU and i >5 ° free of major perturbations; (c) Better defined boundaries for the classical region: 42-47.5 AU (q > 38 AU) for cold classical TNOs and 40-47.5 AU (q > 35 AU) for hot ones, with i = 4.5° as the best threshold to distinguish between both populations; (d) The high inclination TNOs seen in the 40-42 AU region reflect their initial conditions. Therefore they should be classified as hot classical TNOs. Lastly, we report a good match between our results and observations, indicating that the former can provide explanations and predictions for the orbital structure in the classical region. © Springer Science+Business Media, Inc. 2005.
  • Patryk Sofia Lykawka; Tadashi Mukai
    Planetary and Space Science 53 11 1175 - 1187 Elsevier BV 2005年09月 [査読有り]
     
    In the transneptunian classical region (42AU10°. Taking into account those particles still locked in the resonance at the end of the simulations, we determined a retainability of 12-15% for real 7:4 resonant transneptunian objects (TNOs). Lastly, our results demonstrate that classical TNOs associated with the 7:4 mean motion resonance have been evolving continuously until present with non-negligible mixing of populations. © 2005 Elsevier Ltd. All rights reserved.
  • A origem do Sistema Solar e o Cinturao de Kuiper (公開講演) [in Portuguese]
    パトリック ソフィア リカフィカ
    2005年08月
  • A origem do Sistema Solar e o cinturao de Kuiper (招待講演) [in Portuguese]
    パトリック ソフィア リカフィカ
    2005年
  • Lykawka PS; Mukai T
    Bulletin of the American Astronomical Society 36 1102  2004年 [査読有り]
  • Exploring the 7:4 mean motion resonance and other features in the transneptunian belt (招待講演) [in English]
    パトリック ソフィア リカフィカ
    2004年
  • T. Mukai; A. Higuchi; P. S. Lykawka; H. Kimura; I. Mann; S. Yamamoto
    Advances in Space Research 34 1 172 - 178 2004年 [査読有り]
     
    We present our current understandings of small bodies and dust grains located in the outer Solar System. Small icy bodies - Edgeworth-Kuiper Belt objects (EKBOs) and Oort Cloud objects orbit the Sun at distances from Neptune's orbit outward to 10 4 -10 5 AU. Both EKBOs and Oort Cloud objects are believed to be remnants of planetesimals formed in the proto-planetary disk. They provide a possible source for icy bodies that enter the inner Solar System and are observed as comets. A possible scenario for the formation and dynamical evolution of icy objects under the influence of gas drag forces and gravitational scattering by proto-planets is briefly discussed. The outer Solar System plays the role of a corridor for interstellar matter entering into the Solar System. Further dust grains existing beyond Neptune's orbit are produced as ejecta of icy dust particles from the EKBOs due to the impact of interstellar dust grains. Their expected amount and lifetimes are examined. Compared to the extension of the region of planetesimals around the Sun, the region of influence of the solar wind extends to relatively small distances of the order of several hundred AU. But both complexes are coupled through the presence of interstellar dust that depends on the extension and the physical parameters of the heliosphere. The existence of a stronger solar wind in the early stages of the Solar System indicates that the heliosphere in a distant past might have been 10-100 times larger than the current one which possibly influenced the evolution of the planetary system. © 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.
  • Lykawka Patryk Sofia; Mukai Tadashi; 向井正
    title 第 36 回月・惑星シンポジウム Proceedings of the 36th ISAS Lunar and Planetary Symposium 161  2003年 [査読有り]
  • The Edgeworth-Kuiper belt (招待講演) [in Japanese]
    パトリック ソフィア リカフィカ
    2002年
  • 向井 正; 富田 奈津美; 樋口 有理可; リカウカ パトリック; サクラヤン アブ
    日本惑星科学会秋季講演会予稿集 2002 0 19 - 19 日本惑星科学会 2002年

書籍

  • ソフィア・パトリック・リカフィカ; 向井 正 講談社 2008年12月 ISBN: 4062725452 192
  • 講談社プラスアルファ新書, 太陽系に未知の「惑星X」が存在する!
    向井 正; パトリック ソフィア リカフィカ (担当:共著範囲:)講談社 2008年12月

講演・口頭発表等

  • Investigating the orbital structure of the distant Kuiper Belt: Evidence for an undiscovered planet?  [通常講演]
    パトリック ソフィア リカフィカ
    Japan Geoscience Union Meeting 2023年05月
  • Terrestrial planet and asteroid belt formation by Jupiter–Saturn chaotic excitation: A comprehensive dynamical model for the inner solar system  [通常講演]
    パトリック ソフィア リカフィカ
    Japan Geoscience Union Meeting 2023年05月
  • Investigating the orbital structure of the distant Kuiper Belt: Evidence for an undiscovered planet?  [通常講演]
    パトリック ソフィア リカフィカ
    Division for Planetary Sciences (DPS) Meeting 2022年10月
  • Investigating the orbital structure of the distant Kuiper Belt: Evidence for an undiscovered planet?  [通常講演]
    パトリック ソフィア リカフィカ
    Japanese Society for Planetary Sciences Fall Meeting 2022年09月
  • Investigating the existence of a new planet in the outer solar system  [通常講演]
    パトリック ソフィア リカフィカ
    Astronomical Society of Japan Spring Meeting 2022年03月
  • Investigating the existence of a new planet in the far outer solar system  [通常講演]
    パトリック ソフィア リカフィカ
    Division for Planetary Sciences (DPS) Meeting 2021年10月
  • Investigating the existence of a new planet in the far outer solar system  [通常講演]
    パトリック ソフィア リカフィカ
    Japanese Society for Planetary Sciences Fall Meeting 2021年09月
  • Constraining the Formation of the Four Terrestrial Planets in the Solar System  [通常講演]
    Division for Planetary Sciences DPS Meeting 2020年10月 口頭発表（一般）
  • Terrestrial Planet Formation: Constraints on Mercury, Venus, Earth, and Mars  [通常講演]
    ISAS Planetary Exploration Workshop 2020年09月 口頭発表（一般）
  • Constraining the Formation of Mars with N-body simulations of Terrestrial Planet Formation  [通常講演]
    Japan Geosciences Union Meeting-American Geophysical Union Joint Meeting 2020年07月 口頭発表（一般）
  • Constraining the Formation of Venus with N-body simulations of Terrestrial Planet Formation  [通常講演]
    Japan Geosciences Union Meeting-American Geophysical Union Joint Meeting 2020年 口頭発表（一般）
  • Constraining the Formation of the Four Terrestrial Planets in the Solar System: No Success in Narrow Protoplanetary Disks  [通常講演]
    Planet Formation Workshop 2019 2019年 口頭発表（一般）
  • Constraining the formation of the 4 terrestrial planets in the solar system: No success in Grand Tack-like truncated disks and other narrow disks  [通常講演]
    Japanese Society for Planetary Sciences Fall Meeting 2019年 口頭発表（一般）
  • Outer Solar System Origins Survey (OSSOS) Main results and constraints on the Centaurs and scattering trans-Neptunian objects  [招待講演]
    Special Seminar on solar system science 2019年 口頭発表（招待・特別）
  • Terrestrial Planet Formation: Delivery of Water to Mercury and Venus  [通常講演]
    Japan Geosciences Union Meeting 2017年05月 ポスター発表
  • Terrestrial Planet Formation: Constraining the Formation of Mercury  [通常講演]
    Japan Geosciences Union Meeting 2017年05月 口頭発表（一般）
  • Terrestrial Planet Formation: Revealing the conditions for simultaneous formation of Mercury, Venus, Earth, and Mars  [通常講演]
    Japanese Society for Planetary Sciences Fall Meeting 2017年 ポスター発表
  • Dynamical History of Captured Jupiter Trojans and Neighbor Populations  [招待講演]
    Jupiter Trojan 2016: New Insights in Solar System Evolution Symposium 2016年 口頭発表（招待・特別）
  • Orbital Structure and Dynamical Evolution of TNOs  [招待講演]
    Satellite Systems Meeting 2014年 口頭発表（招待・特別）
  • Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets (講演) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Takashi Ito
    第４６回 月・惑星シンポジウムプログラム 2013年08月 Sagamihara, Japan 第４６回 月・惑星シンポジウムプログラム
  • Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets  [招待講演]
    Special Seminar on terrestrial planet formation 2013年06月 口頭発表（招待・特別）
  • Trans-Neptunian Objects as Natural Probes to the Unknown Solar System (招待講演)  [招待講演]
    パトリック ソフィア リカフィカ
    44th American Astronomical Society/Division on Dynamical Astronomy (DDA) Meeting 2013年05月 Paraty, Brazil 44th American Astronomical Society/Division on Dynamical Astronomy (DDA) Meeting
     
    Invited Speaker （招待講演）
  • Trans-Neptunian Objects as Natural Probes to the Unknown Solar System  [通常講演]
    パトリック ソフィア リカフィカ
    44th American Astronomical Society/Division on Dynamical Astronomy (DDA) Meeting 2013年 Paraty, Brazil 44th American Astronomical Society/Division on Dynamical Astronomy (DDA) Meeting
  • On the orbital (in)stability of Trojan asteroids in the solar system (講演) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Thomas Mueller
    “Towards New Explorations of Solar System Small Bodies” Research Meeting 2012年11月 Institute of Space and Astronautical Science (ISAS), Sagamihara, Japan “Towards New Explorations of Solar System Small Bodies” Research Meeting
     
    太陽系におけるトロヤ群天体の軌道安定性について
  • Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets (講演) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Takashi Ito
    Japanese Society for Planetary Sciences Fall Meeting 2012年10月 Kobe, Japan Japanese Society for Planetary Sciences Fall Meeting
  • 初期太陽系における巨大惑星のトロヤ群天体の捕獲と解放 (講演)  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner
    Astronomical Society of Japan Fall Meeting 2012 2012年09月 Oita, Japan Astronomical Society of Japan Fall Meeting 2012
  • The capture and release of Trojan asteroids by the giant planets during the solar system history (講演) [in English]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner
    Japan Geoscience Union Meeting 2012 2012年05月 Chiba, Japan Japan Geoscience Union Meeting 2012
  • Dynamical Evolution of Haumea Collisional Family and Implications for the Outer Solar System  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Tadashi Mukai; Akiko M. Nakamura
    Asteroids, Comets, Meteors 2012 2012年05月 Niigata, Japan Asteroids, Comets, Meteors 2012
  • Origin and dynamical evolution of TNOs  [招待講演]
    Special Seminar on Kuiper Belt and TNOs 2012年 口頭発表（招待・特別）
  • The capture and release of Trojan asteroids by the giant planets during the solar system history  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner
    Astronomical Society of Japan Fall Meeting 2012 2012年 Oita University, Oita, Japan Astronomical Society of Japan Fall Meeting 2012
  • Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets  [通常講演]
    パトリック ソフィア リカフィカ; Takashi Ito
    Japanese Society for Planetary Sciences Meeting 2012 2012年 Kobe University, Kobe, Japan Japanese Society for Planetary Sciences Meeting 2012
  • On the orbital (in)stability of Trojan asteroids in the solar system  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Thomas Mueller
    “Towards New Explorations of Solar System Small Bodies” Research Meeting 2012年 Institute of Space and Astronautical Science (ISAS), Sagamihara, Japan “Towards New Explorations of Solar System Small Bodies” Research Meeting
  • Dynamical Evolution of Haumea Collisional Family and Implications for the Outer Solar System  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Tadashi Mukai; Akiko M. Nakamura
    Asteroids, Comets, Meteors 2012 2012年 Niigata, Japan Asteroids, Comets, Meteors 2012
  • The capture and release of Trojan asteroids by the giant planets during the solar system history  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner
    EPSC-DPS Planetary Sciences Joint Meeting 2011年10月 Nantes, France EPSC-DPS Planetary Sciences Joint Meeting
  • Dynamical evolution of Haumea collisional family: Clues on the collision physics, new family members and implications for the outer solar system  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    EPSC-DPS Planetary Sciences Joint Meeting 2011年10月 Nantes, France EPSC-DPS Planetary Sciences Joint Meeting
  • 準惑星ハウメア衝突族の軌道進化: カイパーベルトの歴史への影響 (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    Japan Geoscience Union Meeting 2011 2011年05月 Chiba, Japan Japan Geoscience Union Meeting 2011
  • Trojan Asteroids and the Early Evolution of the Solar System (講演①) [in English]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    Japan Geoscience Union Meeting 2011 2011年05月 Chiba, Japan Japan Geoscience Union Meeting 2011
  • Trojan asteroids and the early evolution of the solar system (講演) [in English]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie Jones; Tadashi Mukai
    The International Symposium on Planetary Science 2011 2011年03月 Tohoku University, Sendai, Japan The International Symposium on Planetary Science 2011
  • Dynamical evolution of dwarf planet (136108) Haumea collisional family: General properties and implications for the trans-neptunian belt  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    The International Symposium on Planetary Science 2011 2011年03月 Tohoku University, Sendai, Japan The International Symposium on Planetary Science 2011
  • Trojan objects and the origin and evolution of the solar system  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie Jones; Tadashi Mukai
    Astronomical Society of Japan Spring Meeting 2011 2011年 Ibaraki University, Ibaraki, Japan Astronomical Society of Japan Spring Meeting 2011
     
    * The conference was cancelled due to the Kanto-Tohoku earthquake. However, the bulleting containing the abstracts was published by the Society.
  • Trojan Asteroids and the Early Evolution of the Solar System  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    Center for Computational Astrophysics (CfCA) users’ meeting 2011年01月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan Center for Computational Astrophysics (CfCA) users’ meeting
  • The capture and release of Trojan asteroids by the giant planets during the solar system history  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner
    EPSC-DPS Planetary Sciences Joint Meeting 2011年 Nantes, France EPSC-DPS Planetary Sciences Joint Meeting
  • Dynamical evolution of the Haumean family: Effects and implications in the Edgeworth-Kuiper belt  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    Astronomical Society of Japan Spring Meeting 2011 2011年 Ibaraki University, Ibaraki, Japan Astronomical Society of Japan Spring Meeting 2011
     
    * The conference was cancelled due to the Kanto-Tohoku earthquake. However, the bulleting containing the abstracts was published by the Society.
  • Dynamical evolution of Haumea collisional family: Clues on the collision physics, new family members and implications for the outer solar system  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    EPSC-DPS Planetary Sciences Joint Meeting 2011年 Nantes, France EPSC-DPS Planetary Sciences Joint Meeting
  • 準惑星ハウメア衝突族の軌道進化: 一般的な特徴と太陽系外縁帯への影響  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    7th Primordial Bodies Research Meeting 2010年12月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan 7th Primordial Bodies Research Meeting
  • トロヤ群天体と太陽系の初期軌道進化  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    7th Primordial Bodies Research Meeting 2010年12月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan 7th Primordial Bodies Research Meeting
  • Trojan Asteroids and the Early Evolution of the Solar System  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    42nd Division for Planetary Sciences (DPS) Meeting 2010年10月 Pasadena, United States 42nd Division for Planetary Sciences (DPS) Meeting
  • Trojan Asteroids and the Early Evolution of the Giant Planets  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2010 2010年08月 Hyderabad, India Asia Oceania Geosciences Society (AOGS) Meeting 2010
  • Trojan Asteroids and the Early Evolution of the Solar System  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    42nd Division for Planetary Sciences (DPS) Meeting 2010年 Pasadena, United States 42nd Division for Planetary Sciences (DPS) Meeting
  • Origin and dynamical evolution of Haumea’s collisional family in the Kuiper belt [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    Center for Computational Astrophysics (CfCA) users’ meeting 2010年01月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan Center for Computational Astrophysics (CfCA) users’ meeting
  • Origin and Dynamical Evolution of Neptune Trojans [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    5th Primordial Bodies Research Meeting 2009年12月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan 5th Primordial Bodies Research Meeting
  • Origin and Dynamical Evolution of Neptune Trojans  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2009 2009年08月 Singapore Asia Oceania Geosciences Society (AOGS) Meeting 2009
  • Origin and Dynamical Evolution of Neptune Trojans  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    CPS International School of Planetary Sciences 2009年01月 Kobe, Japan CPS International School of Planetary Sciences
  • Long-term dynamical evolution of Haumea’s collisional family in the Kuiper belt [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Akiko M. Nakamura; Tadashi Mukai
    Rironkon Symposium (Theoretical Astronomy) 2008 2008年12月 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan Rironkon Symposium (Theoretical Astronomy) 2008
  • Origin and Dynamical Evolution of Neptune Trojans (講演①) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Barrie W. Jones; Tadashi Mukai
    Japanese Society for Planetary Sciences Fall Meeting 2008年10月 Fukuoka, Japan Japanese Society for Planetary Sciences Fall Meeting
  • Long-term evolution of trans-Neptunian objects: Effects of multiple temporary captures in mean motion resonances (講演②) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japanese Society for Planetary Sciences Fall Meeting 2008年10月 Fukuoka, Japan Japanese Society for Planetary Sciences Fall Meeting
  • Origin of the Edgeworth-Kuiper Belt Architecture: Evidence of Dynamical Sculpting by an Outer Planet (講演①)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asteroids, Comets, Meteors 2008 2008年07月 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Origin and Dynamical Evolution of Neptune Trojans (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Tadashi Mukai; Barrie W. Jones
    Asteroids, Comets, Meteors 2008 2008年07月 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Long-Term Dynamical Evolution of Trans-Neptunian Objects in the Scattered Disk (講演③)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asteroids, Comets, Meteors 2008 2008年07月 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Long-term Dynamical Evolution of Trans-Neptunian Objects in Scattered Orbits (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2008 2008年06月 Busan, Korea Asia Oceania Geosciences Society (AOGS) Meeting 2008
  • Dynamical Classification of Trans-Neptunian Objects: New Clues on the Origin and Evolution of the Outer Solar System (講演①)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2008 2008年06月 Busan, Korea Asia Oceania Geosciences Society (AOGS) Meeting 2008
  • Long-term evolution of trans-Neptunian objects: Effects of multiple temporary captures in mean motion resonances [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japan Geosciences Union Meeting 2008 2008年05月 Chiba, Japan Japan Geosciences Union Meeting 2008
  • Origin and Dynamical structure of the Trans-Neptunian Belt  [招待講演]
    Kansai Star & Planet Formation Seminar 2008年 口頭発表（招待・特別）
  • Origin of the Edgeworth-Kuiper Belt Architecture: Evidence of Dynamical Sculpting by an Outer Planet  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asteroids, Comets, Meteors 2008 2008年 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Origin and dynamical evolution of Neptune Trojans  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Tadashi Mukai; Barrie Jones
    Japanese Society for Planetary Sciences Meeting 2008 2008年 Kyushu University, Fukuoka, Japan Japanese Society for Planetary Sciences Meeting 2008
  • Origin and Dynamical Evolution of Neptune Trojans  [通常講演]
    パトリック ソフィア リカフィカ; Jonathan Horner; Tadashi Mukai; Barrie W. Jones
    Asteroids, Comets, Meteors 2008 2008年 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Long-Term Dynamical Evolution of Trans-Neptunian Objects in the Scattered Disk  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asteroids, Comets, Meteors 2008 2008年 Baltimore, United States Asteroids, Comets, Meteors 2008
  • Impact Cratering Experiments to Targets with Cavity: Application to Cave Skylight on Mars  [通常講演]
    Tatsuhiro Michikami; パトリック ソフィア リカフィカ; S. Miura; J. Haruyama
    39th Lunar and Planetary Science Conference 2008年 League City, United States 39th Lunar and Planetary Science Conference
  • Trans-Neptunian belt architecture: Evidence for a distant planet in the solar system  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japanese Society for Planetary Sciences Meeting 2007 2007年 Kochi University, Kochi, Japan Japanese Society for Planetary Sciences Meeting 2007
  • Trans-Neptunian Region Architecture: Evidence for a Planet Beyond Pluto (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japan Geosciences Union Meeting 2007 2007年 Chiba, Japan Japan Geosciences Union Meeting 2007
  • Trans-Neptunian Region Architecture: Evidence for a Planet Beyond Pluto (講演①)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2007 2007年 Bangkok, Thailand Asia Oceania Geosciences Society (AOGS) Meeting 2007
  • Trans-Neptunian Belt Architecture: Evidence for a Distant Planet in the Solar System (講演①) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japanese Society for Planetary Sciences Fall Meeting 2007年 Kouchi, Japan Japanese Society for Planetary Sciences Fall Meeting
  • Origin of scattered disk resonant TNOs: Evidence for an ancient excited Kuiper belt of 50AU radius  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japanese Society for Planetary Sciences Meeting 2007 2007年 Kochi University, Kochi, Japan Japanese Society for Planetary Sciences Meeting 2007
  • Origin of Scattered Disk Resonant TNOs: Evidence for an Ancient Excited Kuiper Belt of 50AU Radius (講演②) [in Japanese]  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japanese Society for Planetary Sciences Fall Meeting 2007年 Kouchi, Japan Japanese Society for Planetary Sciences Fall Meeting
  • Origin of Scattered Disk Resonant TNOs: Evidence for an Ancient Excited Kuiper Belt of 50AU Radius (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2007 2007年 Bangkok, Thailand Asia Oceania Geosciences Society (AOGS) Meeting 2007
  • Origin of Scattered Disk Resonant TNOs: Evidence for an Ancient Excited Kuiper Belt of 50AU Radius (講演①)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Japan Geosciences Union Meeting 2007 2007年 Chiba, Japan Japan Geosciences Union Meeting 2007
  • Long-term evolution and resonance sticking of scattered disk objects (講演②)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    European Planetary Science Congress 2007 2007年 Potsdam, Germany European Planetary Science Congress 2007
  • An outer planet beyond Pluto and the origin of Kuiper belt architecture (講演①)  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    European Planetary Science Congress 2007 2007年 Potsdam, Germany European Planetary Science Congress 2007
  • An outer planet and the origin of Kuiper Belt architecture  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Kobe International School of Planetary Sciences 2007年 Kobe, Japan Kobe International School of Planetary Sciences
  • A Distant Massive Planet Beyond Pluto and Origin of Kuiper Belt Architecture  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    39th Division for Planetary Sciences (DPS) Meeting 2007年 Orlando, United States 39th Division for Planetary Sciences (DPS) Meeting
  • A Distant Massive Planet Beyond Pluto and Origin of Kuiper Belt Architecture  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    42nd Division for Planetary Sciences (DPS) Meeting 2007年 Orlando, United States 42nd Division for Planetary Sciences (DPS) Meeting
  • Trans-Neptunian Region Architecture: Evidence for a Planet Beyond Pluto  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Kobe International School of Planetary Sciences 2006年 Kobe, Japan Kobe International School of Planetary Sciences
  • The transneptunian region architecture: a formation scenario  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Workshop Trans-Neptunian Objects: Dynamical and Physical properties 2006年 Catania, Italy Workshop Trans-Neptunian Objects: Dynamical and Physical properties
  • Resonance occupancy in the transneptunian region: dynamical properties and implications  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    XVIIIth Rencontres de Blois Planetary Science: challenges and discoveries 2006年 Blois, France XVIIIth Rencontres de Blois Planetary Science: challenges and discoveries
  • Origin of Resonant TNOs: Evidence for an Ancient Excited Kuiper Belt of 50AU Radius  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    American Geophysical Union, Fall Meeting 2006 2006年 San Francisco, United States American Geophysical Union, Fall Meeting 2006
  • Origin of Resonant TNOs: Evidence for an Ancient Excited Kuiper Belt of 50AU Radius  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    American Geophysical Union (AGU) Fall Meeting 2006年 San Francisco, United States American Geophysical Union (AGU) Fall Meeting
  • Origin and evolution of the trans-Neptunian region (招待講演) [in English]  [招待講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    2nd COE Symposium: Cross Talk between Chemistry and Planetary Sciences 2006年 口頭発表（招待・特別） Kobe University, Kobe, Japan 2nd COE Symposium: Cross Talk between Chemistry and Planetary Sciences
  • A origem do Sistema Solar e o cinturão de Kuiper
    Special Physics Seminars 2005年 口頭発表（招待・特別）
  • The transneptunian region architecture: revelations from observations and theoretical results  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Kobe International School of Planetary Sciences 2005年 Awaji Island, Japan Kobe International School of Planetary Sciences
  • Dynamical structure and physical properties of classical transneptunian objects  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asteroids, Comets, Meteors 2005 2005年 Buzios, Brazil Asteroids, Comets, Meteors 2005
  • Exploring the 7:4 mean motion resonance and other features in the transneptunian belt  [招待講演]
    Kansai Star & Planet Formation Seminar 2004年 口頭発表（招待・特別）
  • Exploring the 7:4 mean motion resonance and dynamical evolution of transneptunian objects  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Asia Oceania Geosciences Society (AOGS) Meeting 2004 2004年 Singapore Asia Oceania Geosciences Society (AOGS) Meeting 2004
  • Exploring evolutionary paths and resonance sticking of scattered transneptunian objects  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    36th Division for Planetary Sciences (DPS) Meeting 2004年 Louisville, United States 36th Division for Planetary Sciences (DPS) Meeting
  • Dynamical structures in the classical transneptunian belt and scattered region  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    Transneptunian Objects - 10 years since first observation Workshop 2004年 National Astronomical Observatory of Japan (NAOJ), Mitaka, Japan Transneptunian Objects - 10 years since first observation Workshop
  • The 7:4 mean motion resonance and dynamical structures in the classical transneptunian belt  [通常講演]
    パトリック ソフィア リカフィカ; Tadashi Mukai
    36th ISAS Lunar and Planetary Symposium 2003年 Institute of Space and Astronautical Science (ISAS), Sagamihara, Japan 36th ISAS Lunar and Planetary Symposium
  • Solar Perturbation Forces on Small Body in Early Solar System  [通常講演]
    Tadashi Mukai; パトリック ソフィア リカフィカ; Abu Md. Saklayen; Arika Higuchi; Natsuki Tomita
    Japanese Society for Planetary Sciences Meeting 2002 2003年 水沢市文化会館 Japanese Society for Planetary Sciences Meeting 2002
  • The Edgeworth-Kuiper belt  [招待講演]
    Summer School for university undergraduate students 2002年 公開講演，セミナー，チュートリアル，講習，講義等
  • Perturbation Forces on Small Asteroids  [通常講演]
    Abu Md. Saklayen; パトリック ソフィア リカフィカ; Arika Higuchi; Natsuki Tomita; Tadashi Mukai
    35th ISAS Lunar and Planetary Symposium 2002年 Institute of Space and Astronautical Science (ISAS), Sagamihara, Japan 35th ISAS Lunar and Planetary Symposium

MISC

受賞

  • http://sites.google.com/site/patryksofialykawka/ https://tinyurl.com/2v4ns2jr
     履歴書を見てください（ダイレクトリンクあるいはURL） 
    受賞者: パトリック ソフィア リカフィカ

共同研究・競争的資金等の研究課題

  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    研究期間 : 2023年04月 -2026年03月
  • ➞ ダイレクトリンク https://tinyurl.com/2v4ns2jr あるいはURL： http://sites.google.com/site/patryksofialykawka/：
    研究期間 : 2001年 -2026年 
    代表者 : パトリック ソフィア リカフィカ
  • Japan Society for the Promotion of Science：Grants-in-Aid for Scientific Research
    研究期間 : 2020年04月 -2023年03月
  • 日本学術振興会：科学研究費助成事業 特別研究員奨励費
    研究期間 : 2007年 -2008年 
    代表者 : 向井 正; LYKAWKA P.S.; P.S. Lykawka
     
    海王星軌道以遠に発見されている氷天体(太陽系外縁天体;TNOsと呼ぶ)の空間分布とそれらの起源について、諸天体の軌道進化の数値シミュレーションに基づく研究を行った。加えて、木星以遠の巨大ガス惑星や、惑星系外縁部の初期環境や、その後の進化の過程を明らかにした。大規模数値シミュレーションは、N体系の軌道進化を50億年にわたって追跡するもので、得られた結果は、現在の観測量と比較検討した。その結果、TNOsのみならず、巨大惑星の軌道進化や、天体軌道の力学共鳴の過程、太陽系の起源と進化について有益な成果が得られた。主な成果を列挙すると、 (1)カイパーベルト全域の太陽系外縁天体の軌道分布に基づく分類を突施し、それらの空間構造の起源を明らかにした。この際、「新惑星」の存在を仮定すると、太陽系外縁天体の軌道分布の特異性が説明できるというモデルを提案した。 (2)地球サイズの新惑星による影響が、太陽系の起源と進化シナリオに与える制約を明らかにした。 (3)海王星軌道に発見されているトロヤ群の起源と軌道進化の数値シミュレーションから、海王星トロヤ群がその場で生まれたものと、海王星移動時に捕獲されたものの混合群である事を示した。 (4)カイパーベルトに発見されているハウメア衝突族の起源を明らかにするために、衝突破片の軌道進化の数値シミュレーションを実行し、この族が生まれてきた過程を明確にした。また、今後、新メンバーが観測によって発見される可能性を示唆した。 これらの結果は、4件の雑誌論文と6件の国内外の学会で発表した。

担当経験のある科目

  • 履歴書を見てください ➞ ダイレクトリンク https://tinyurl.com/2v4ns2jr あるいはURL： http://sites.google.com/site/patryksofialykawka/近畿大学

メディア報道

  • 履歴書を見てください ➞ ダイレクトリンク https://tinyurl.com/2v4ns2jr あるいはURL： http://sites.google.com/site/patryksofialykawka/
    執筆者 : 本人

学術貢献活動

  • 履歴書を見てください ➞ ダイレクトリンク https://tinyurl.com/2v4ns2jr あるいはURL： http://sites.google.com/site/patryksofialykawka/
    役割 : 監修
    種別 : 審査・学術的助言

その他

  • 2016年04月 - 2016年04月  水星・金星・地球・火星の形成と水の起源の解明 
    近畿大学学内研究助成金 奨励研究助成金 SR07 研究課題「水星・金星・地球・火星の形成と水の起源の解明」の研究報告書。詳細はKURepo参照。

その他のリンク

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