研究者業績

吉川 真

ヨシカワ マコト  (Makoto YOSHIKAWA)

基本情報

所属
国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 宇宙機応用工学研究系 はやぶさ2プロジェクト 准教授
学位
理学博士(1989年3月 東京大学)

連絡先
yoshikawa.makotojaxa.jp
J-GLOBAL ID
200901037361657011
researchmap会員ID
1000304540

学歴

 2

受賞

 2

論文

 278
  • Maria Schönbächler, Manuela A. Fehr, Tetsuya Yokoyama, Ikshu Gautam, Nao Nakanishi, Yoshinari Abe, Jérôme Aléon, Conel Alexander, Sachiko Amari, Yuri Amelin, Ken‐ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W. Carlson, Marc Chaussidon, Byeon‐Gak Choi, Nicolas Dauphas, Andrew M. Davis, Tommaso Di Rocco, Wataru Fujiya, Ryota Fukai, Makiko K. Haba, Yuki Hibiya, Hiroshi Hidaka, Hisashi Homma, Peter Hoppe, Gary R. Huss, Kiyohiro Ichida, Tsuyoshi Iizuka, Trevor Ireland, Akira Ishikawa, Shoichi Itoh, Noriyuki Kawasaki, Noriko T. Kita, Koki Kitajima, Thorsten Kleine, Shintaro Komatani, Alexander N. Krot, Ming‐Chang Liu, Yuki Masuda, Mayu Morita, Kazuko Motomura, Frédéric Moynier, Izumi Nakai, Kazuhide Nagashima, Ann Nguyen, Larry Nittler, Morihiko Onose, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, Sara Russell, Naoya Sakamoto, Lauren Tafla, Haolan Tang, Kentaro Terada, Yasuko Terada, Tomohiro Usui, Sohei Wada, Meenakshi Wadhwa, Richard J. Walker, Katsuyuki Yamashita, Qing‐Zhu Yin, Shigekazu Yoneda, Edward D. Young, Hiroharu Yui, Ai‐Cheng Zhang, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tatsuaki Okada, Toru Yada, Kasumi Yogata, Satoru Nakazawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Sei‐ichiro Watanabe, Makoto Yoshikawa, Shogo Tachibana, Hisayoshi Yurimoto
    Meteoritics & Planetary Science 2024年11月25日  
    Abstract Nucleosynthetic isotope variations are powerful tracers to determine genetic relationships between meteorites and planetary bodies. They can help to link material collected by space missions to known meteorite groups. The Hayabusa 2 mission returned samples from the Cb‐type asteroid (162173) Ryugu. The mineralogical, chemical, and isotopic characteristics of these samples show strong similarities to carbonaceous chondrites and in particular CI chondrites. The nucleosynthetic isotope compositions of Ryugu overlap with CI chondrites for several elements (e.g., Cr, Ti, Fe, and Zn). In contrast to these isotopes, which are of predominately supernovae origin, s‐process variations in Mo isotope data are similar to those of carbonaceous chondrites, but even more s‐process depleted. To further constrain the origin of this depletion and test whether this signature is also present for other s‐process elements, we report Zr isotope compositions for three bulk Ryugu samples (A0106, A0106‐A0107, C0108) collected from the Hayabusa 2 mission. The data are complemented with that of terrestrial rock reference materials, eucrites, and carbonaceous chondrites. The Ryugu samples are characterized by distinct 96Zr enrichment relative to Earth, indicative of a s‐process depletion. Such depletion is also observed for carbonaceous chondrites and eucrites, in line with previous Zr isotope work, but it is more extreme in Ryugu, as observed for Mo isotopes. Since s‐process Zr and Mo are coupled in mainstream SiC grains, these distinct s‐process variations might be due to SiC grain depletion in the analyzed materials, potentially caused by incomplete sample digestion, because the Ryugu samples were dissolved on a hotplate only to avoid high blank levels for other elements (e.g., Cr). However, local depletion of SiC grains cannot be excluded. An alternative, equally possible scenario is that aqueous alteration redistributed anomalous, s‐process‐depleted, Zr on a local scale, for example, into Ca‐phosphates or phyllosilicates.
  • Fridolin Spitzer, Thorsten Kleine, Christoph Burkhardt, Timo Hopp, Tetsuya Yokoyama, Yoshinari Abe, Jérôme Aléon, Conel M. O’D Alexander, Sachiko Amari, Yuri Amelin, Ken-ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W. Carlson, Marc Chaussidon, Byeon-Gak Choi, Nicolas Dauphas, Andrew M. Davis, Tommaso Di Rocco, Wataru Fujiya, Ryota Fukai, Ikshu Gautam, Makiko K. Haba, Yuki Hibiya, Hiroshi Hidaka, Hisashi Homma, Peter Hoppe, Gary R. Huss, Kiyohiro Ichida, Tsuyoshi Iizuka, Trevor R. Ireland, Akira Ishikawa, Shoichi Itoh, Noriyuki Kawasaki, Noriko T. Kita, Kouki Kitajima, Shintaro Komatani, Alexander N. Krot, Ming-Chang Liu, Yuki Masuda, Mayu Morita, Fréderic Moynier, Kazuko Motomura, Izumi Nakai, Kazuhide Nagashima, Ann Nguyen, Larry Nittler, Morihiko Onose, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, Sara S. Russell, Naoya Sakamoto, Maria Schönbächler, Lauren Tafla, Haolan Tang, Kentaro Terada, Yasuko Terada, Tomohiro Usui, Sohei Wada, Meenakshi Wadhwa, Richard J. Walker, Katsuyuki Yamashita, Qing-Zhu Yin, Shigekazu Yoneda, Edward D. Young, Hiroharu Yui, Ai-Cheng Zhang, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tatsuaki Okada, Toru Yada, Kasumi Yogata, Satoru Nakazawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Sei-ichiro Watanabe, Makoto Yoshikawa, Shogo Tachibana, Hisayoshi Yurimoto
    Science Advances 10(39) 2024年9月27日  
    The isotopic compositions of samples returned from Cb-type asteroid Ryugu and Ivuna-type (CI) chondrites are distinct from other carbonaceous chondrites, which has led to the suggestion that Ryugu/CI chondrites formed in a different region of the accretion disk, possibly around the orbits of Uranus and Neptune. We show that, like for Fe, Ryugu and CI chondrites also have indistinguishable Ni isotope anomalies, which differ from those of other carbonaceous chondrites. We propose that this unique Fe and Ni isotopic composition reflects different accretion efficiencies of small FeNi metal grains among the carbonaceous chondrite parent bodies. The CI chondrites incorporated these grains more efficiently, possibly because they formed at the end of the disk’s lifetime, when planetesimal formation was also triggered by photoevaporation of the disk. Isotopic variations among carbonaceous chondrites may thus reflect fractionation of distinct dust components from a common reservoir, implying CI chondrites/Ryugu may have formed in the same region of the accretion disk as other carbonaceous chondrites.
  • Bradley De Gregorio, George D. Cody, Rhonda M. Stroud, A. L. David Kilcoyne, Scott Sandford, Corentin Le Guillou, Larry R. Nittler, Jens Barosch, Hikaru Yabuta, Zita Martins, Yoko Kebukawa, Taiga Okumura, Minako Hashiguchi, Shohei Yamashita, Yasuo Takeichi, Yoshio Takahashi, Daisuke Wakabayashi, Cécile Engrand, Laure Bejach, Lydie Bonal, Eric Quirico, Laurent Remusat, Jean Duprat, Maximilien Verdier-Paoletti, Smail Mostefaoui, Mutsumi Komatsu, Jérémie Mathurin, Alexandre Dazzi, Ariane Deniset-Besseau, Emmanuel Dartois, Yusuke Tamenori, Hiroki Suga, Gilles Montagnac, Kanami Kamide, Miho Shigenaka, Megumi Matsumoto, Yuma Enokido, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Tomohiro Usui, Masanao Abe, Tatsuaki Okada, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Ryuji Okazaki, Hiroshi Naraoka, Kanako Sakamoto, Shogo Tachibana, Sei-ichiro Watanabe, Yuichi Tsuda
    Nature Communications 15 7488 2024年8月29日  査読有り
    Abstract Primordial carbon delivered to the early earth by asteroids and meteorites provided a diverse source of extraterrestrial organics from pre-existing simple organic compounds, complex solar-irradiated macromolecules, and macromolecules from extended hydrothermal processing. Surface regolith collected by the Hayabusa2 spacecraft from the carbon-rich asteroid 162173 Ryugu present a unique opportunity to untangle the sources and processing history of carbonaceous matter. Here we show carbonaceous grains in Ryugu can be classified into three main populations defined by spectral shape: Highly aromatic (HA), Alkyl-Aromatic (AA), and IOM-like (IL). These carbon populations may be related to primordial chemistry, since C and N isotopic compositions vary between the three groups. Diffuse carbon is occasionally dominated by molecular carbonate preferentially associated with coarse-grained phyllosilicate minerals. Compared to related carbonaceous meteorites, the greater diversity of organic functional chemistry in Ryugu indicate the pristine condition of these asteroid samples.
  • Hiroharu Yui, Shu-hei Urashima, Morihiko Onose, Mayu Morita, Shintaro Komatani, Izumi Nakai, Yoshinari Abe, Yasuko Terada, Hisashi Homma, Kazuko Motomura, Kiyohiro Ichida, Tetsuya Yokoyama, Kazuhide Nagashima, Jérôme Aléon, Conel M. O’D. Alexander, Sachiko Amari, Yuri Amelin, Ken-ichi Bajo, Martin Bizzarro, Audrey Bouvier, Richard W. Carlson, Marc Chaussidon, Byeon-Gak Choi, Nicolas Dauphas, Andrew M. Davis, Wataru Fujiya, Ryota Fukai, Ikshu Gautam, Makiko K. Haba, Yuki Hibiya, Hiroshi Hidaka, Peter Hoppe, Gary R. Huss, Tsuyoshi Iizuka, Trevor R. Ireland, Akira Ishikawa, Shoichi Itoh, Noriyuki Kawasaki, Noriko T. Kita, Kouki Kitajima, Thorsten Kleine, Sasha Krot, Ming-Chang Liu, Yuki Masuda, Frédéric Moynier, Ann Nguyen, Larry Nittler, Andreas Pack, Changkun Park, Laurette Piani, Liping Qin, Tommaso Di Rocco, Sara S. Russell, Naoya Sakamoto, Maria Schönbächler, Lauren Tafla, Haolan Tang, Kentaro Terada, Tomohiro Usui, Sohei Wada, Meenakshi Wadhwa, Richard J. Walker, Katsuyuki Yamashita, Qing-Zhu Yin, Shigekazu Yoneda, Edward D. Young, Ai-Cheng Zhang, Tomoki Nakamura, Hiroshi Naraoka, Takaaki Noguchi, Ryuji Okazaki, Kanako Sakamoto, Hikaru Yabuta, Masanao Abe, Akiko Miyazaki, Aiko Nakato, Masahiro Nishimura, Tatsuaki Okada, Toru Yada, Kasumi Yogata, Satoru Nakazawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Yuichi Tsuda, Sei-ichiro Watanabe, Makoto Yoshikawa, Shogo Tachibana, Hisayoshi Yurimoto
    Geochimica et Cosmochimica Acta 379 172-183 2024年8月  
  • Yoshinori Takano, Hiroshi Naraoka, Jason P. Dworkin, Toshiki Koga, Kazunori Sasaki, Hajime Sato, Yasuhiro Oba, Nanako O. Ogawa, Toshihiro Yoshimura, Kenji Hamase, Naohiko Ohkouchi, Eric T. Parker, José C. Aponte, Daniel P. Glavin, Yoshihiro Furukawa, Junken Aoki, Kuniyuki Kano, Shin Ichiro M. Nomura, Francois Regis Orthous-Daunay, Philippe Schmitt-Kopplin, Hisayoshi Yurimoto, Tomoki Nakamura, Takaaki Noguchi, Ryuji Okazaki, Hikaru Yabuta, Kanako Sakamoto, Toru Yada, Masahiro Nishimura, Aiko Nakato, Akiko Miyazaki, Kasumi Yogata, Masanao Abe, Tatsuaki Okada, Tomohiro Usui, Makoto Yoshikawa, Takanao Saiki, Satoshi Tanaka, Fuyuto Terui, Satoru Nakazawa, Sei Ichiro Watanabe, Yuichi Tsuda, Shogo Tachibana
    Nature communications 15(1) 5708 2024年7月10日  
    We report primordial aqueous alteration signatures in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu by the Hayabusa2 spacecraft of JAXA. Newly identified low-molecular-weight hydroxy acids (HO-R-COOH) and dicarboxylic acids (HOOC-R-COOH), such as glycolic acid, lactic acid, glyceric acid, oxalic acid, and succinic acid, are predominant in samples from the two touchdown locations at Ryugu. The quantitative and qualitative profiles for the hydrophilic molecules between the two sampling locations shows similar trends within the order of ppb (parts per billion) to ppm (parts per million). A wide variety of structural isomers, including α- and β-hydroxy acids, are observed among the hydrophilic molecules. We also identify pyruvic acid and dihydroxy and tricarboxylic acids, which are biochemically important intermediates relevant to molecular evolution, such as the primordial TCA (tricarboxylic acid) cycle. Here, we find evidence that the asteroid Ryugu samples underwent substantial aqueous alteration, as revealed by the presence of malonic acid during keto-enol tautomerism in the dicarboxylic acid profile. The comprehensive data suggest the presence of a series for water-soluble organic molecules in the regolith of Ryugu and evidence of signatures in coevolutionary aqueous alteration between water and organics in this carbonaceous asteroid.

MISC

 499
  • 中島潤一, 木内等, 関戸衛, 花土ゆう子, 岩田隆浩, 近藤哲朗, 吉川真
    日本天文学会年会講演予稿集 1994 1994年  
  • 吉川真
    日本天文学会年会講演予稿集 1994 1994年  
  • 中村士, 吉川真
    日本天文学会年会講演予稿集 1994 1994年  
  • 毛利勝広, 鈴木雅夫, 北原政子, 安田孝美, 東海彰吾, 吉川真, 沢武文
    日本天文学会年会講演予稿集 1994 1994年  
  • 磯部しゅう三, 吉川真
    日本天文学会年会講演予稿集 1994 1994年  
  • 吉川真
    日本天文学会年会講演予稿集 1994 1994年  
  • 吉川 真
    日本航海学会誌 NAVIGATION 119 32-40 1994年  
    宇宙にある'ごみ'であるスペースデブリが近年非常に多くなってきており,今後の宇宙利用や宇宙開発にとって大きな障害になる懸念が広がってきている。このことは,GPSを利用したり,静止軌道の衛星を今後活用していこうとしている現在の航海技術にとっても他人事ではない。この報告では,このスペースデブリについてまずその現状を簡単にまとめてみることにする。次に,特に静止軌道付近にあるスペースデブリについてその軌道運動を解析した結果を報告する。
  • 吉川 真, 木村 和宏
    天文月報 87(1) p28-33 1994年1月  
  • Journal of the Communications Research Laboratory 41 185-194 1994年  
  • M YOSHIKAWA
    SEVENTY-FIVE YEARS OF HIRAYAMA ASTEROID FAMILIES: THE ROLE OF COLLISIONS IN THE SOLAR SYSTEM HISTORY 63 28-38 1994年  
  • 吉川 真
    遊・星・人 : 日本惑星科学会誌 2(4) 164-172 1993年12月1日  
  • Tsuko Nakamura, Makoto Yoshikawa
    Celestial Mechanics & Dynamical Astronomy 57(1-2) 113-121 1993年10月  
    We investigated by numerical integrations the long-term orbital evolution of four giant comets or comet-like objects. They are Chiron, P/Schwassmann-Wachmann 1 (SW1), Hidalgo, and 1992AD (5145), and their orbits were traced for 100-200 thousand years (kyr) toward both the past and the future. For each object, 13 orbits were calculated, one for the nominal orbital elements and other 12 with slightly modified elements based on the rms residual of the orbit determination and on the number of observations. As past studies indicate, their orbital evolution is found to be very chaotic, and thus can be described only in terms of probability. Plots of the semi-major axis (a) and perihelion distance (q) of the objects treated here seem to cross each other frequently, suggesting a possibility of their common evolutionary paths. About a half of all the calculated orbits showed q- or a-decreasing evolution. This indicates that, at least on the time scale in question, the giant comet-like objects are possibly on a dynamical track that can lead to capture from the outer solar system. We could hardly find the orbits with perihelia far outside the orbit of Saturn (q>15 AU). This is perhaps because the evolution of the orbits beyond Saturn is so slow that substantial orbital changes do not take place within 100-200 kyr. © 1993 Kluwer Academic Publishers.
  • 吉川 真
    情報通信研究機構研究報告 39(4) 261-273 1993年  
  • 細川瑞彦, 吉川真
    日本天文学会年会講演予稿集 1993 1993年  
  • 吉川真, 中村士
    日本天文学会年会講演予稿集 1993 1993年  
  • 中村士, 吉川真
    日本天文学会年会講演予稿集 1993 1993年  
  • 吉川真
    月惑星ジャーナル (8) 6-7 1993年  筆頭著者
  • 吉川真
    通信総合研究所季報 39(4) 261-273 1993年  
  • 吉川真
    天文月報 86(2) 73-74 1993年  
  • K OHTSUKA, M YOSHIKAWA, J WATANABE
    METEOROIDS AND THEIR PARENT BODIES 73-76 1993年  
  • Tsuko Nakamura, Makoto Yoshikawa
    Celestial Mechanics and Dynamical Astronomy 54(1-3) 261-266 1992年3月  
    We systematically surveyed the orbits of short-period (SP) comets that show a large change of perihelion distance (q) between 1-2 AU (visible comets) and 4-5 AU (invisible comets) during 4400 years. The data are taken from Cosmo-DICE (Nakamura and Yoshikawa 1991a), which is a long-term orbital evolution project for SP comets. Recognizing that q is the most critical element for observability of comets, an invisibility factor (f), defined as the ratio of unobservable time span to observable span during 4400 years, is calculated for each of the large-q-change comets. A detection limit for each comet is obtained from the heliocentric distance at discovery and/or the absolute magnitude at recent apparitions. A mean f value for 35 SP comets with 2.9 ≤ J (J is the Tisserand's invariant) is found to be 19.8. This implies that for each visible SP comet of this J-range, at every epoch of time, there exist about 20 invisible comets near the capture orbits by Jupiter, under the assumptions of steady-state flux and ergodicity for the SP-comet population. © 1992 Kluwer Academic Publishers.
  • Makoto Yoshikawa
    Celestial Mechanics and Dynamical Astronomy 54(1-3) 287-290 1992年3月  
    Motions of asteroids in mean motion resonances with Jupiter are studied in three-dimensional space. Orbital changes of fictitious asteroids in the Kirkwood gaps are calculated by numerical integrations for 10 - 10 years. The main results are as follows: (1) There are various motions of resonant asteroids, and some of them are very complicated and chaotic and others are regular. (2) The eccentricity of some asteroids becomes very large, and the variation of the inclination is large while the eccentricity is large. (3) In the 3:1 resonance, there is a long periodic change in the variation of the inclination, when (ω7 : Ω) is a simple ratio (ω7: longitude of perihelion, Ω: longitude of node). (4) In the 7:3 resonance, the variation of the inclination of some resonant asteroids is so large that prograde motion becomes retrograde. Some asteroids in the 7:3 resonance can collide with the Sun as well as with the inner planets. © 1992 Kluwer Academic Publishers. 5 6
  • 吉川真
    日経サイエンス 1992(10) 14-21 1992年  
  • 中村士, 吉川真
    日本天文学会年会講演予稿集 1992 1992年  
  • Proceedings of the eighteenth international symposium on space technology and science 2403-2408 1992年  
  • Makoto Yoshikawa
    Icarus 92(1) 94-117 1991年7月  
    The behavior of asteroids at the 5:2, 7:3, and 2:1 resonances with Jupiter is studied in the scheme of the elliptical restricted three-body problem. Following the previous study of Yoshikawa (1990, Icarus, 87, 78-102), the motions of asteroids are investigated by using semianalytical and numerical methods. In semianalytical models, the effect of the inclination of asteroids is taken into account. In numerical integrations, however, only planar cases are treated, but large parameter regions are investigated. The results are summarized as follows: (1) in the 5:2 resonance, the eccentricities of orbits of asteroids change greatly in most of the resonance region, (2) in the 7:3 resonance, the eccentricities of asteroids change greatly mainly in the central part of the resonance region, and (3) in the 2:1 resonance, the eccentricities of asteroids do not change greatly in most of the resonance region. This result for the 2:1 resonance is in agreement with Lemaître and Henrard (1990, Icarus 83, 391-409). Considering these results and the result of Yoshikawa (1990), we can say that the origin of the Kirkwood gaps at the 3:1 and 5:2 resonances can be explained by the scenario of collision with major planets, which was first proposed by Wisdom (1982, Astron. J. 87, 577-593). However, within the restriction of our study, the results obtained here do not support this scenario for the gaps at the 7:3 and 2:1 resonances. In order to reveal the formation mechanism of these gaps, we should study more general cases, that is, the motions of asteroids in three-dimensional space under the perturbation of several planets. © 1991.
  • 吉川真, 中村士
    日本天文学会年会講演予稿集 1991 1991年  
  • 渡部潤一, 中村卓司, 津田敏隆, 堤雅基, 宮下暁彦, 吉川真
    日本天文学会年会講演予稿集 1991 1991年  
  • 中村士, 吉川真
    日本天文学会年会講演予稿集 1991 1991年  
  • 吉川真
    日本天文学会年会講演予稿集 1991 1991年  
  • Tsuko Nakamura, Makoto Yoshikawa
    Publications of National Astronomical Observatory of Japan 2(2) 293-383 1991年  
  • Makoto Yoshikawa
    Icarus 87(1) 78-102 1990年9月  
    The behavior of asteroids at the 3:1 resonance is studied in a large parameter region, and the various motions that these asteroids show are summarized. First, the motions of asteroids are investigated qualitatively using a semianalytical method, and the variations of (a, σ) and (e, ω) are obtained graphically for various values of the parameters (a = semimajor axis, σ = critical argument, e = eccentricity, ω = longitude of perihelion). Next, to know the motions of asteroids more quantitatively, the orbital changes in asteroids are calculated by numerical integrations in the scheme of a planar elliptical restricted three-body problem. The main results are as follows: (1) The variations in a and σ are rather complicated, and the variations in e and ω depend strictly on the behavior of these elements. (2) The region where the resonance occurs is obtained on the a-e plane, and almost all numbered asteroids avoid this region. (3) The eccentricities of most asteroids in the resonance region change markedly (Δe {greater-than or approximate} 0.2 or much larger), and these changes take place in a period of 10 -10 years. (4) In terms of the orbital changes of asteroids, the resonance region shows a complicated structure. © 1990. 4 5
  • 木下宙, 吉川真
    日本天文学会年会講演予稿集 1990(shuki) 1990年  
  • 吉川真
    日本天文学会年会講演予稿集 1990(shuki) 1990年  
  • 吉川 真
    天文月報 82(11) p280-285 1989年11月  
  • M YOSHIKAWA
    ASTRONOMY & ASTROPHYSICS 213(1-2) 436-458 1989年4月  
  • 吉川真
    惑星科学 7(2-3) 189-192 1989年  
  • H SCHOLL, C FROESCHLE, H KINOSHITA, M YOSHIKAWA, JG WILLIAMS
    ASTEROIDS II 845-861 1989年  
  • 吉川 真
    物性研究 50(2) 129-142 1988年  
    この論文は国立情報学研究所の電子図書館事業により電子化されました。
  • 吉川 真
    素粒子論研究 77(3) C63-C76 1988年  
    The motions of asteroids in the mean motion resonances with Jupiter are investigated by a semi-analytical model. By using this model, it is found that eccentricities of asteroids may become very large when asteroids are in one of the resonances. These large increases in eccentricity are also confirmed by the numerical integrations. The gaps in the asteroidal belt can be explained by these large variations of eccentricities. It is known that asteroids show chaotic behavior when they are in the mean motion resonances. In this paper, the chaotic behavior of asteroids in the 7:3 resonance is shown.
  • Makoto Yoshikawa
    Vistas in Astronomy 31(C) 151-154 1988年  
    The motions of asteroids in the secular resonance υ 6 are investigated by a simple analytical model. By using this model, it is found that eccentricities of asteroids may become very large (e ∼ 0.8) when asteroids are in or near this resonance. These large increases in eccentricity are also confirmed by numerical integrations. The strongly depopulated region in the asteroidal belt, which corresponds to the position of the secular resonance υ6, is explained well by this analytical model. © 1988.
  • Makoto Yoshikawa
    Celestial Mechanics 40(3-4) 233-272 1987年9月  
    When asteroids are in the secular resonance ν , the variation of the eccentricity becomes very large. In this paper, the dynamics of this secular resonance ν is investigated by a simple analytical model, in which the third degree terms of the eccentricity and inclination are taken into account. The eccentricity variations of asteroids located near this resonance are represented clearly by the diagrams of equi-Hamiltonian curves on the plane of {Mathematical expression} versus e ( {Mathematical expression} the longitude of perihelion of asteroids and Saturn, e: the eccentricity of asteroids). These diagrams predict that the eccentricity of these asteroids suffers a large increase or decrease, and that the secular resonance argument {Mathematical expression} librates about 0° and 180°. In order to confirm these predictions, numerical integrations are carried out over one million years. By these integrations, it is found that the eccentricity of secular resonant asteroids becomes more than 0.8, and that the libration about 0° also exists, as well as the libration about 180°. The strongly depopulated region in the asteroidal belt, which corresponds to the position of the secular resonance ν , is also explained well by this analytical model. © 1987 D. Reidel Publishing Company. 6 6 6
  • Annals of the Tokyo Astronomical Observatory, Second Series (]G0010[)(]G0010[)(]G0001[)(3) 323-356 1987年  
  • 青木 勉, 濱部 勝, 濱武 久司, 市川 伸一, 石田 [けい]一, 伊藤 昌尚, 泉浦 秀行, 香西 洋樹, 前原 英夫, 野口 猛, 岡村 定矩, 征矢野 隆夫, 田中 亘, 谷口 義明, 樽沢 賢一, 山縣 朋彦, 吉川 真, 渡辺 正明
    宇宙科学研究所報告. 特集: 太陽風と彗星の相互作用研究報告 15(15) 133-143 1986年9月  
    資料番号: SA0166726000

書籍等出版物

 19

講演・口頭発表等

 32

担当経験のある科目(授業)

 8

共同研究・競争的資金等の研究課題

 15

学術貢献活動

 3

社会貢献活動

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メディア報道

 2