Theory of Star Formation in Different Environments from the Solar Neighborhood

• Project/Area Number: 18740117
• 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: OMUKAI Kazuyuki National Astronomical Observatory of Japan, 理論研究部, 助教 (70390622)
• Project Period (FY): 2006 – 2008
• Project Status: Completed (Fiscal Year 2008)
• Budget Amount: ¥3,400,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥300,000); Fiscal Year 2008: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2007: ¥1,000,000 (Direct Cost: ¥1,000,000); Fiscal Year 2006: ¥1,100,000 (Direct Cost: ¥1,100,000)
• Keywords: 星形成 / 金属欠乏星 / 銀河形成 / 宇宙論 / 星間物質 / 宇宙初代星

Research Abstract

将来の大望遠鏡による観測の指針とすることを目指し、形成期銀河の環境である低金属度ガス中での星形成過程を理論的に考察した。まずは重元素を全く含まない宇宙最初の星の形成過程を化学反応・輻射過程を取り組んだ三次元流体シミュレーションを用いて調べ、宇宙最初の星が太陽の100倍を越える巨大なものであったことを発見した。またこのような星が連星となり条件などについても考察した。次に第二世代以降の星形成の際に重要となる、微量の重元素の効果についても調べ、どの程度の重元素があれば太陽と同じくらいの小さい星が生まれるのか考察し、そのためには星間微粒子の存在が必要であることを見出した。

Research Products

• [Journal Article] Evolution of Massive Protostars with High Accretion Rates (2009)
  • Author(s): T. Hosokawa, & K. Omukai
  • Journal Title: The Astrophysical Journal 691 Pages: 823-846
  • Peer Reviewed
• [Journal Article] Can Supermassive Black Holes Form in the Metal-Enriched High-redshift Protogalaxies? (2008)
  • Author(s): K. Omukai, R. Schneider, & Z. Haiman
  • Journal Title: The Astrophysical Journal 686 Pages: 801-814
  • Peer Reviewed
• [Journal Article] Protostar Formation in the Early Universe (2008)
  • Author(s): N. Yoshida, K. Omukai, & L. Hernquist
  • Journal Title: Science 321 Pages: 669-671
  • Peer Reviewed
• [Journal Article] Conditions for the Formation of First-Star Binaries (2008)
  • Author(s): M. N. Machida, K. Omukai, T. Matsumoto, & S. Inutsuka
  • Journal Title: The Astrophysical Journal 677 Pages: 813-827
  • Peer Reviewed
• [Journal Article] Physical Mechanism for the Intermediate Characteristic Stellar Mass in the Extremely Metal-Poor Environments (2008)
  • Author(s): T. Tsuribe & K. Omukai
  • Journal Title: The Astrophysical Journal 676
  • Peer Reviewed
• [Journal Article] Can Supermassive Black Holes Form in Metal-enriched High-redshift Protogalaxies (2008)
  • Author(s): K. Omukai, R. Schneider, & Z. Haiman
  • Journal Title: The Astrophysical Journal 686 Pages: 801-814
  • Peer Reviewed
• [Journal Article] Physical Mechanism for the Intermediate Characteristic Stellar Mass in Extremely Metal Poor Environments (2008)
  • Author(s): Tsuribe, T., Omukai, K.
  • Journal Title: ApJ 676
  • Peer Reviewed
• [Journal Article] Formation of Massive Primordial Stars in a Reionized Gas (2007)
  • Author(s): N. Yoshida, K. Omukai, & L. Hernquist
  • Journal Title: The Astrophysical Journal 667
  • Peer Reviewed
• [Journal Article] The radio to infrared emission of very high redshift gamma-ray bursts : probing early star formation through molecular and atomic absorption lines (2007)
  • Author(s): S. Inoue, K. Omukai, & B. Ciardi
  • Journal Title: Monthly Notices of the Royal Astronomical Society 380 Pages: 1715-1728
  • Peer Reviewed
• [Journal Article] Formation of Massive Primordial Stars in a Reionized Gas (2007)
  • Author(s): Yoshida, N., Omukai, K., Hernquist, L.
  • Journal Title: ApJ 667
  • Peer Reviewed
• [Journal Article] The radio to infrared emission of very high redshift gamma-ray bursts: probing early star formation through molecular and atomic absorption lines (2007)
  • Author(s): Inoue, S., Omukai, K., Ciardi, B.
  • Journal Title: MNRAS 380 Pages: 1715-1728
  • Peer Reviewed
• [Journal Article] Dust-cooling--induced Fragmentation of Low-metallicity Clouds (2006)
  • Author(s): T. Tsuribe, & K. Omukai
  • Journal Title: The Astrophysical Journal 642
  • Peer Reviewed
• [Journal Article] Fragmentation of star-forming clouds enriched with the first dust (2006)
  • Author(s): R. Schneider, K. Omukai, A. K. Inoue, & A. Ferrara
  • Journal Title: Monthly Notices of the Royal Astronomical Society 369 Pages: 1437-1444
  • Peer Reviewed
• [Journal Article] The First Jets in the Universe : Protostellar Jets from the First Stars (2006)
  • Author(s): M. N. Machida, K. Omukai, T. Matsumoto, & S. Inutsuka
  • Journal Title: The Astrophysical Journal 647
  • Peer Reviewed
• [Journal Article] Formation of Primordial Stars in a ΛCDM Universe (2006)
  • Author(s): N. Yoshida, K. Omukai, L. Hernquist, & T. Abel
  • Journal Title: The Astrophysical Journal 652 Pages: 6-25
  • Peer Reviewed
• [Journal Article] Dust-cooling-induced Fragmentation of Low-Metallicity Clouds (2006)
  • Author(s): Tsuribe, T., Omukai, K.
  • Journal Title: The Astrophysical Journal 642
• [Journal Article] Fragmentation of star-forming clouds enriched with the first dust (2006)
  • Author(s): Schneider, R., Omukai, K., Inoue, A.K., Ferrara, A.
  • Journal Title: Monthly Notices of the Royal Astronomical Society 369 Pages: 1437-1444
• [Journal Article] The First Jets in the Universe : Protostellar Jets from the First Stars (2006)
  • Author(s): Machida, M.N., Omukai, K., Matsumoto, T., Inutsuka, S.
  • Journal Title: The Astrophysical Journal 647
• [Journal Article] Formation of Primordial Stars in a A CDM Universe (2006)
  • Author(s): Yoshida, N., Omukai, K., Hernquist, L., Abel, T.
  • Journal Title: The Astrophysical Journal 652 Pages: 6-25
• [Presentation] Low-metallicity star formation : the characteristic mass and upper mass limit (2008)
  • Author(s): 大向一行
  • Organizer: IAUシンポジウム255
  • Place of Presentation: Rapallo, Italy
  • Year and Date: 2008-07-16
• [Presentation] Low-metallicity star formation : the characteristic mass and upper masslimit (2008)
  • Author(s): 大向一行
  • Organizer: TAU 255 Symposium : Low-metallicity Star Formation
  • Place of Presentation: Rapallo, Italy
  • Year and Date: 2008-07-16
• [Presentation] 低金属量星の形成 (2007)
  • Author(s): 大向一行
  • Organizer: 日本天文学会2007年秋季年会
  • Place of Presentation: 岐阜大学
  • Year and Date: 2007-09-28
• [Presentation] Zero-metallicity Protostar Formation (2007)
  • Author(s): 大向一行
  • Organizer: 会議 "Star Formation, Then and Now"
  • Place of Presentation: UC Santa Barbara, USA
  • Year and Date: 2007-08-13
• [Presentation] Zero-metallicity Protostar Formation (2007)
  • Author(s): K. Omukai
  • Organizer: Star Formation, Then and Now
  • Place of Presentation: UC Santa Barbara, USA
  • Year and Date: 2007-08-13
• [Presentation] The formation of stars at very low metallicity (2007)
  • Author(s): 大向一行
  • Organizer: First Stars III
  • Place of Presentation: Santa Fe, USA
  • Year and Date: 2007-07-16
• [Presentation] Radiative feedback from the first stars and formation of the second-generation stars (2007)
  • Author(s): 大向一行
  • Organizer: HI Survival through Cosmic Times
  • Place of Presentation: Abbazia di Spineto, Italy
  • Year and Date: 2007-06-11
• [Presentation] Radiative feedback from the first stars and formation of the second-generation stars (2007)
  • Author(s): K. Omukai
  • Organizer: HI Survival through Cosmic Times
  • Place of Presentation: Abbazia di Spineto, ltaly
  • Year and Date: 2007-06-11