A Study of the Stars and the Structure Formation History in the Early Universe

2010 Fiscal Year Final Research Report

• Project/Area Number: 18104003
• Research Category: Grant-in-Aid for Scientific Research (S)
• Allocation Type: Single-year Grants
• Research Field: Astronomy
• Research Institution: Hokkaido University
• Principal Investigator: FUJIMOTO Masayuki 北海道大学, 大学院・理学研究院, 教授 (00111708)
• Co-Investigator(Kenkyū-buntansha): NOMOTO Ken'ichi 東京大学, 数物連携宇宙研究機構, 特任教授 (90110676) ; KOZASA Takashi 北海道大学, 大学院・理学研究院, 教授 (90263368) ; AOKI Wako 国立天文台, 光赤外研究部, 助教 (20321581) ; SUDA Takuma 国立天文台, 光赤外研究部, 博士研究員 (90374735) ; TSUJI Takashi 東京大学, 名誉教授 (20011546)
• Project Period (FY): 2006 – 2010
• Keywords: 恒星進化 / 元素合成 / 恒星大気 / 宇宙塵 / 銀河系形成

Research Abstract

Recent presence of stars with heavier elements other than hydrogen and helium less than a thousandth of the solar abundances is revealed thanks to large-scale surveys and high dispersion spectroscopy studies with large telescope of diameter 8m for the Galactic halo. These stars are the low-mass survivors of the stars formed in early Universe just after the Big Bang. In this study, we investigate the characteristics of these extremely metal-poor stars theoretically and observationally to explore what are the first stars born first and in early stage in our Universe. In addition, with these stars as probe, we study and derive a new picture on the early evolution of Universe and the formation process of our Milky Way galaxy.

Research Products

• [Journal Article] The Stellar Abundances for Galactic Archaeology (SAGA) Database II-Implications for Mixing and Nucleosynthesis in Extremely Metal-Poor Stars and Chemical Enrichment of the Galaxy (2011)
  • Author(s): T. Suda, S. Yamada, Y. Katsuta, Y. Komiya, C. Ishizuka, T. Nishimura, W. Aoki, M. Y. Fujimoto
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: Vol.412, No.2 Pages: 843-874
  • Peer Reviewed
• [Journal Article] Formation of Dust in the Ejecta of Type Ia Supernovae (2011)
  • Author(s): Nozawa, T., Maeda, K., Kozasa, T., Tanaka, M., Nomoto, K., Umeda, H
  • Journal Title: Astrophysical Journal Volume: Vol.736, No.1 Pages: 45-57
  • Peer Reviewed
• [Journal Article] The Role of Dust in the Early Universe. I. Protogalaxy Evolution (2011)
  • Author(s): Yamasawa, D., Habe, A., Kozasa, T., Nozawa, T., Hirashita, H., Umeda, H., Nomoto, K
  • Journal Title: Astrophysical Journal Volume: Vol.735, No.44 Pages: 44-57
  • Peer Reviewed
• [Journal Article] Formation History of Metal-poor Halo Stars with the Hierarchical Model and the Effect of Interstellar Matter Accretion on the Most Metal-poor Stars (2010)
  • Author(s): Komiya, Y., Habe, A., Suda, T., Fujimoto, M. Y.
  • Journal Title: Astrophysical Journal Volume: vol.717, No.1 Pages: 542-561
  • Peer Reviewed
• [Journal Article] Evolution of low-and intermediate-mass stars with [Fe/H] <=-2.5 (2010)
  • Author(s): Suda, T., Fujimoto, M. Y.
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: Vol.405, No.1 Pages: 177-193
  • Peer Reviewed
• [Journal Article] Oxygen and Light Element Synthesis by Neutron-Capture Reactions in Metal-Free and Extremely Metal-Poor AGB Stars (2009)
  • Author(s): Takanori, Nishimura, Masayuki Aikawa
  • Journal Title: Publication of the Astronomical Society of Japan Volume: vol.61, No.5 Pages: 909-929
  • Peer Reviewed
• [Journal Article] Hierarchical Formation of the Galactic Halo and the Origin of Hyper Metal-Poor Stars (2009)
  • Author(s): Y. Komiya, A. Habe, T. Suda, M.Y. Fujimoto
  • Journal Title: Astrophysical Journal Letters Volume: vol.696, No.1 Pages: L79-L83
  • Peer Reviewed
• [Journal Article] Early-Age Evolution of the Milky Way Related by Extremely Metal-Poor Stars (2009)
  • Author(s): Y. Komiya, T. Suda, and M. Y. Fujimoto
  • Journal Title: Astrophysical Journal Volume: vol.694 Pages: 1577-1594
  • Peer Reviewed
• [Journal Article] Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turnoff Stars from the SDSS SEGUE Sample (2008)
  • Author(s): Aoki, W., Beers, T. C., Sivarani, T. Marsteller, B., Lee, Y.S., Honda, S., Norris, J. E. Ryan, S., Carollo, D.
  • Journal Title: Astrophysical Journal Volume: Vol.678, No.2 Pages: 1351-1371
  • Peer Reviewed
• [Journal Article] Asphericity in Supernova Explosions from Late-Time Spectroscopy (2008)
  • Author(s): Maeda, K. Nomoto, K., 他16名
  • Journal Title: Science Volume: Vol.319, No.5867 Pages: 1220-1223
  • Peer Reviewed
• [Journal Article] Stellar Abundances for the Galactic Archeology (SAGA) Database-Compilation of the Characteristics of Known Extremely Metal-Poor Stars (2008)
  • Author(s): T. Suda, Yutaka. Katsuta, Shimako. Yamada, Tamon. Suwa, Chieko. Ishizuka, Y. Komiya, Kazuo., Sorai, M. Aikawa, and M. Y. Fujimoto
  • Journal Title: Publication of the Astronomical Society of Japan Volume: vol.60, No.5 Pages: 1159-1171
  • Peer Reviewed
• [Journal Article] Extinction curves flattened by reverse shocks in supernovae (2008)
  • Author(s): H. Hirashita, T. Nozawa, T.T. Takeuchi, T. Kozasa
  • Journal Title: Monthly Notices of the Royal Astronomical Society Volume: Vol.384, No.2 Pages: 1725-1732
  • Peer Reviewed
• [Journal Article] Formation of Dust in the Ejecta of Type Ib SN 2006jc and Temperature and Mass of the Dust (2008)
  • Author(s): Nozawa, T., Kozasa, T., Tominaga, N., Sakon, I., Tanaka, M., Suzuki, T., Nomoto, K., Maeda, K., Umeda, H., Limongi, M., Onaka, T.
  • Journal Title: Astrophysical Journal Volume: Vol.684, No.3 Pages: 1343-1350
  • Peer Reviewed
• [Journal Article] Carbon-enhanced Metal-poor Stars. I. Chemical Compositions of 26 Stars (2007)
  • Author(s): W. Aoki, T. C. Beers, N. Christlieb, J. E. Norris, S. G. Ryan, S. Tsangarides
  • Journal Title: Astrophysical Journal Volume: vol.655, No.1 Pages: 492-521
  • Peer Reviewed
• [Journal Article] The Aspherical Properties of the Energetic Type Ic SN 2002ap as Inferred from Its Nebular Spectra (2007)
  • Author(s): P. A. Mazzali K. Nomoto, 他11名
  • Journal Title: Astrophysical Journal Volume: vol.670, No.1 Pages: 592-599
  • Peer Reviewed
• [Journal Article] The Connection between Gamma-Ray Bursts and Extremely Metal-Poor Stars : Black-Hole Forming Supernovae with Relativistic Jets (2007)
  • Author(s): N. Tominaga, K. Maeda, H. Umeda, K. Nomoto, M., N. Iwamoto, T. Suzuki, A. Mazzali
  • Journal Title: Astrophysical Journal Volume: vol.657, No.2 Pages: L77-L80
  • Peer Reviewed
• [Journal Article] Evolution of Dust in Primordial Supernova Remnants : Can Dust Grains Formed in the Ejecta Survive and Be Injected into the Early Interstellar Medium? (2007)
  • Author(s): T. Nozawa, T. Kozasa, A. Habe, E. Dwek, H. Umeda, N.Tominaga, K. Maeda, K. Nomoto
  • Journal Title: Astrophysical Journal Volume: Vol.666, No.2 Pages: 955-966
  • Peer Reviewed
• [Journal Article] The Origin of Carbon-Enhancement and Initial Mass Function of Extremely Metal-Poor Stars in the Galactic Halo (2007)
  • Author(s): Y. Komiya, T. Suda, H. Minaguchi, T. Shigeyama, W. Aoki, and M.Y. Fujimoto
  • Journal Title: Astrophysical Journal Volume: Vol.658, No.1 Pages: 367-390
  • Peer Reviewed
• [Presentation] (2007)
  • Author(s): M. Y. Fujimoto,(Char), T, Kozasa(Co-Chair), W. Aoki(Co-char), T. Suda(Co-Chair), K., Nomoto, 他13名
  • Organizer: 10th internal Symposium on Origin of Matter and Evolution of Galaxies (OMEG10), LOC
  • Place of Presentation: Sapporo, Japan
  • Year and Date: 20071204-7
• [Remarks] SAGA(銀河考古学のための星の組成)データベース(The Stellar Abundances for Galactic Archaeology Database)
  • URL: http://saga.sci.hokudai.ac.jp/