Thermal and Dynamical Evolution of Primordial Gas Clouds. On the Formation of First Luminous Objects.

• Nishi Ryoichi

  Department of Physics, Kyoto University, Kyoto 606–8502, Japan

• Susa Hajime

  Center for Computational Physics, University of Tsukuba Tsukuba 305–8571, Japan

• Uehara Hideya

  Division of Theoretical Astrophysics, National Astronomical Observatory Mitaka 181–8588, Japan

• Yamada Masako

  Department of Physics, Kyoto University, Kyoto 606–8502, Japan

• Omukai Kazuyuki

  Department of Physics, Kyoto University, Kyoto 606–8502, Japan

書誌事項

タイトル別名

• Thermal and Dynamical Evolution of Prim

抄録

We investigate the thermal and dynamical evolution of primordial gas clouds in the universe after decoupling. Comparing the time scale of dynamical evolution with that of fragmentation, we can estimate the typical fragmentation scale. We propose the following scenario of the formation process of first luminous objects consisting of large number stars. First, by pancake collapse of the overdensity regions in the expanding universe or collision between clouds in potential wells, quasi-plane shocks form. If the shock-heated temperature is higher than about 10⁴ K, the post-shock gas cools down to several hundred K by H₂ line cooling, and the shock-compressed layer fragments into filamentary clouds. The filamentary cloud collapses dynamically once more and fragments into cloud cores. Finally, a primordial star forms in a cloud core. We show that the minimum mass of the first star is essentially determined by the it Chandrasekhar mass . Also, we investigate the dynamical collapse of cloud cores by numerical simulation and show that the evolution paths of the central regions of the cores depend only very weakly on the total core mass. After mass accretion, a massive star may be formed in a core, since the estimated mass accretion rate is very large. In such a case, it may be possible for many massive stars form almost simultaneously. Then the clouds can be luminous objects. On the other hand, if the shock-heated temperature is lower, effective star formation is delayed significantly.

収録刊行物

• Ｐｒｏｇｒｅｓｓ　ｏｆ　Ｔｈｅｏｒｅｔｉｃａｌ　Ｐｈｙｓｉｃｓ

  Ｐｒｏｇｒｅｓｓ　ｏｆ　Ｔｈｅｏｒｅｔｉｃａｌ　Ｐｈｙｓｉｃｓ 100 (5), 881-903, 1998

  一般社団法人 日本物理学会

キーワード

• Physics and Astronomy (miscellaneous)

詳細情報

• CRID: 1390001204157234304
• NII論文ID: 110001200698
• NII論文ID: 210000110255
• NII書誌ID: AA00791455
• DOI: 10.1143/ptp.100.881
• BIBCODE: 1998PThPh.100..881N
• ISSN: 13474081
• ISSN: 0033068X
• NDL書誌ID: 4616000
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4616000
• Web Site: http://academic.oup.com/ptp/article-pdf/100/5/881/5282429/100-5-881.pdf
• 本文言語コード: en
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