Exploring Formation of Terrestrial Planets by a Special-Purpose Simulator

• Project/Area Number: 18740116
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Single-year Grants
• Research Field: Astronomy
• Research Institution: National Astronomical Observatory of Japan
• Principal Investigator: KOKUBO Eiichiro National Astronomical Observatory of Japan, 理論研究部, 准教授 (90332163)
• Project Period (FY): 2006 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥3,710,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥210,000); Fiscal Year 2008: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2007: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 2006: ¥1,600,000 (Direct Cost: ¥1,600,000)
• Keywords: 理論天文学 / 惑星系形成 / 太陽系形成 / 地球型惑星 / 多体シミュレーション

Research Abstract

地球のような岩石でできた惑星の形成の最終段階は原始惑星とよばれる火星サイズの天体の衝突合体と考えられている。この過程を専用シミュレータを用いてシミュレーションを行うことによって明らかにした。標準的な初期条件を用いた場合、内惑星領域では典型的に2個の地球サイズの惑星と1-2個の小さめの惑星が形成されることがわかった。これは現在の太陽系と同じである。惑星の最大質量は原始惑星の全質量に比例する。また、惑星の自転角速度は分裂しない最大の角速度くらいになり、自転軸の傾きは90度のものが多いことがわかった。

Research Products

• [Journal Article] Angular Momentum Accretion onto a Gas Giant Planet (2008)
  • Author(s): Machida, M. N., Kokubo, E., Inutsuka, S., Matsumoto, T.
  • Journal Title: The Astrophysical Journal 685 Pages: 1220-1236
  • Peer Reviewed
• [Journal Article] Formation of Terrestrial Planets from Protoplanets. II. Statistics of Planetary Spin (2007)
  • Author(s): Kokubo, E., Ida, S.
  • Journal Title: The Astrophysical Journal 671 Pages: 2082-2090
  • Peer Reviewed
• [Journal Article] Orbital Evolution of Planetesimals due to the Galactic Tide : Formation of the Oort Cloud (2007)
  • Author(s): Higuchi, A., Kokubo, E., Kinoshita, H., Mukai, T.
  • Journal Title: The Astronomical Journal 134 Pages: 1693-1706
  • Peer Reviewed
• [Journal Article] N-Body Simulation of Planetesimal Formation through Gravitational Instability of a Dust Layer (2007)
  • Author(s): Michikoshi, M., Inutsuka, S., Kokubo, E., Furuya, I.
  • Journal Title: The Astrophysical Journal 657 Pages: 521-532
  • Peer Reviewed
• [Journal Article] Formation of Terrestrial Planets from Protoplanets. II. Statistics of Planetary Spin (2007)
  • Author(s): Kokubo, E., Ida, S
  • Journal Title: The Astriphysical Journal 671 Pages: 2082-2090
  • Peer Reviewed
• [Journal Article] Orbital Evolution of Planetesimals due to the Galactic Tide: Formation of the Oort Cloud (2007)
  • Author(s): Higuchi, A., Kokubo, E., Kinoshita, H., Mukai, T.
  • Journal Title: The Astronomical Journal 134 Pages: 1693-1706
  • Peer Reviewed
• [Journal Article] N-Body Simulation of Planetesimal Formation through Gravitational Instability of a Dust Layer (2007)
  • Author(s): S.Michikoshi
  • Journal Title: The Astrophysical Journal 657 Pages: 521-532
• [Journal Article] Formation of Terrestrial Planets from Protoplanets. I. Statistics of Basic Dynamical Properties (2006)
  • Author(s): Kokubo, E., Ida, S.
  • Journal Title: The Astrophysical Journal 642 Pages: 1131-1139
  • Peer Reviewed
• [Journal Article] Formation of Terrestrial Planets from Protoplanets. I. Statistics of Basic Dynamical Properties (2006)
  • Author(s): E.Kokubo
  • Journal Title: The Astrophysical Journal 642 Pages: 1131-1139
• [Presentation] 惑星系の多様性の起源 (2009)
  • Author(s): 小久保英一郎
  • Organizer: 日本天文学会
  • Place of Presentation: 大阪
  • Year and Date: 2009-03-26
• [Presentation] Formation of Terrestrial Planets from Protoplanets (2009)
  • Author(s): Kokubo, E.
  • Organizer: Exoplanets and Disks : Their Formation and Diversity
  • Place of Presentation: Kona (USA)
• [Presentation] Formation of Terrestrial Planets from Protoplanets (2009)
  • Author(s): Kokubo, E.
  • Organizer: Exoplanets and Disks : Their Formation and Diversity
  • Place of Presentation: Kona USA
• [Presentation] 現実的な条件合体のもとでの地球型惑星の自転 (2008)
  • Author(s): 小久保英一郎,玄田英典,井田茂
  • Organizer: 日本天文学会春季年会
  • Place of Presentation: 国立オリンピック記念青少年総合センター
  • Year and Date: 2008-03-25
• [Presentation] 現実的な条件合体のもとでの地球型惑星の自転 (2008)
  • Author(s): 小久保英一郎, 玄田英典, 井田茂
  • Organizer: 日本天文学会
  • Place of Presentation: 代々木
  • Year and Date: 2008-03-25
• [Presentation] Formation of Terrestrial Planets from Protoplanets (2008)
  • Author(s): Kokubo, E.
  • Organizer: 2008 AGU Fall Meeting
  • Place of Presentation: San Francisco (USA)
• [Presentation] Dynamics of Planetary Accretion (2008)
  • Author(s): Kokubo, E.
  • Organizer: The Third East-Asia Numerical Astrophysics Meeting
  • Place of Presentation: Nanjing (China)
• [Presentation] Formation of Planetary Systems (2008)
  • Author(s): Kokubo, E.
  • Organizer: Accretion and Outflow in Astrophysics 2008
  • Place of Presentation: Kyoto (Japan)
• [Presentation] Formation of Terrestrial Planets under a Realistic Accretion Condition (2008)
  • Author(s): Kokubo, E.
  • Organizer: The 10th Asian-Pacific Regional IAU Meeting
  • Place of Presentation: Kunming (China)
• [Presentation] Formation of Terrestrial Planets (2008)
  • Author(s): Kokubo, E.
  • Organizer: Origin and Evolution of Planets 2008
  • Place of Presentation: Asconaスイス
• [Presentation] Formation of Terrestrial Planets under a Realistic Accretion Condition (2008)
  • Author(s): Kokubo, E.
  • Organizer: The 10th Asian-Pacific Regional IAU Meeting
  • Place of Presentation: Kunming中国
• [Presentation] Dynamics of Planetary Accretion (2008)
  • Author(s): Kokubo, E.
  • Organizer: The Third East-Asia Numerical Astrophysics Meeting
  • Place of Presentation: Nanjing中国
• [Presentation] Formation of Terrestrial Planets from Protoplanets (2008)
  • Author(s): Kokubo, E.
  • Organizer: 2008 AGU Fall Meeting
  • Place of Presentation: San Francisco USA
• [Presentation] Formation of Terrestrial Planets from Protoplanets : Effects of Conditional Accretion (2007)
  • Author(s): Kokubo, E., Genda, H., Ida, S.
  • Organizer: IAU Symposium 249 Exoplanets : Detection, Formation and Dynamics
  • Place of Presentation: Suzhou (China)
  • Year and Date: 2007-10-25
• [Presentation] Formation of Terrestrial Planets from Protoplanets: Effects of Conditional Accretion (2007)
  • Author(s): Kokubo, E., Genda, H., Ida, S.
  • Organizer: IAU Symposium 249 Exoplanets: Detection, Formation and Dynamics
  • Place of Presentation: 蘇州
  • Year and Date: 2007-10-25
• [Presentation] 地球型惑星の自転-合体条件の効果 (2007)
  • Author(s): 小久保英一郎,玄田英典,井田茂
  • Organizer: 日本天文学会秋季年会
  • Place of Presentation: 岐阜大学
  • Year and Date: 2007-09-28
• [Presentation] 地球惑星の自転-合体条件の效果 (2007)
  • Author(s): 小久保英一郎, 玄田英典, 井田茂
  • Organizer: 日本天文学会
  • Place of Presentation: 岐阜
  • Year and Date: 2007-09-28
• [Presentation] 原始惑星からの地球型惑星形成-不完全集積の影響 (2007)
  • Author(s): 小久保英一郎,玄田英典,井田茂
  • Organizer: 日本惑星科学会秋季講演会
  • Place of Presentation: 高知大学朝倉キャンパス
  • Year and Date: 2007-09-26
• [Presentation] 原始惑星からの地球型惑星形成-不完全集積の影響 (2007)
  • Author(s): 小久保英一郎, 玄田英典, 井田茂
  • Organizer: 日本惑星科学会
  • Place of Presentation: 高知
  • Year and Date: 2007-09-26
• [Presentation] 最小質量円盤モデル再訪-巨大衝突による地球型惑星形成モデルから (2007)
  • Author(s): 小久保英一郎,井田茂
  • Organizer: 日本天文学会春季年会
  • Place of Presentation: 東海大学湘南キャンパス,平塚
  • Year and Date: 2007-03-29
• [Presentation] Formation of Terrestrial Planets from Protoplanets : Statistics of Planetary Spin (2007)
  • Author(s): Kokubo, E., Ida, S.
  • Organizer: Extreme Solar System
  • Place of Presentation: Santorini (Greece)
• [Presentation] Formation of Terrestrial Planets from Protoplanets: Statistics of Planetary Spin (2007)
  • Author(s): Kokubo, E., Ida, S.
  • Organizer: Extreme Solar System
  • Place of Presentation: Santorini
• [Presentation] 地球型惑星形成の原始惑星分布領域幅依存性 (2006)
  • Author(s): 小久保英一郎,井田茂
  • Organizer: 日本惑星科学会秋季講演会
  • Place of Presentation: 兵庫県立美術館,神戸
  • Year and Date: 2006-10-19
• [Presentation] 原始惑星からの地球型惑星形成-原始惑星分布領域幅依存性 (2006)
  • Author(s): 小久保英一郎,井田茂
  • Organizer: 日本天文学会秋季年会
  • Place of Presentation: 九州国際大学,北九州
  • Year and Date: 2006-09-21
• [Presentation] 巨大衝突による地球型惑星の自転 (2006)
  • Author(s): 小久保英一郎,井田茂
  • Organizer: 地球惑星科学連合大会
  • Place of Presentation: 幕張メッセ国際会議場
  • Year and Date: 2006-05-16
• [Presentation] 地球型惑星の自転 (2006)
  • Author(s): 小久保英一郎,井田茂
  • Organizer: 日本天文学会春季年会
  • Place of Presentation: 和歌山大学
  • Year and Date: 2006-03-29
• [Presentation] From Protoplanets to Terrestrial Planets: Statistica Properties of Assembled Planets (2005)
  • Author(s): Kokubo, E.
  • Organizer: 37th Annual Meeting of the AAS Division for Planetary Sciences
  • Place of Presentation: Campbridge (UK)
  • Year and Date: 2005-09-04
• [Presentation] Formation of Terrestrial Planets and the Origin of Water on the Earth (2005)
  • Author(s): Kokubo, E.
  • Organizer: International Symposium on Origins of Life and Astrobiology
  • Place of Presentation: Niigata (Japan)
  • Year and Date: 2005-07-01
• [Presentation] From Protoplanets to Terrestrial Planets (2005)
  • Author(s): Kokubo, E.
  • Organizer: Early Earth Symposium
  • Place of Presentation: Makuhari (Japan)
  • Year and Date: 2005-05-20
• [Presentation] Protoplanets to Terrestrial Planets (2005)
  • Author(s): Kokubo, E.
  • Organizer: Planet Formation and Detection
  • Place of Presentation: Aspen (USA)
  • Year and Date: 2005-02-09
• [Presentation] Terrestrial Planet Formation from Protoplanets (2005)
  • Author(s): Kokubo, E., Kominami, J., Ida, S.
  • Organizer: Protostars and Planets V
  • Place of Presentation: Waikoloa (USA)
• [Book] 宇宙はどこまで明らかになったのか (2007)
  • Author(s): 小久保英一郎,福江純・粟野由美
  • Publisher: ソフトバンククリエイティブ
• [Remarks] 本研究の成果も使用して製作されたCG映像「地球と月の誕生」が一般向けに以下のURLで公開されている
  • URL: http://4d2u.nao.ac.jp/t/var/download/index.php?id=EarthAndMoon
• [Remarks] 本研究とその成果を使用して製作されたCGが倉敷科学センターのプラネタリウム番組「私たちは星のかけら〜太陽系が生まれる〜」として平成20年11月7日-平成21年3月1日に公開された
  • URL: http://www2.city.kurashiki.okayama.jp/lifepark/ksc/pdf/gkake.pdf