論文

査読有り
2016年6月

FORMATION OF MASSIVE PRIMORDIAL STARS: INTERMITTENT UV FEEDBACK WITH EPISODIC MASS ACCRETION

ASTROPHYSICAL JOURNAL
  • Takashi Hosokawa
  • ,
  • Shingo Hirano
  • ,
  • Rolf Kuiper
  • ,
  • Harold W. Yorke
  • ,
  • Kazuyuki Omukai
  • ,
  • Naoki Yoshida

824
2
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.3847/0004-637X/824/2/119
出版者・発行元
IOP PUBLISHING LTD

We present coupled stellar evolution (SE) and 3D radiation-hydrodynamic (RHD) simulations of the evolution of primordial protostars, their immediate environment, and the dynamic accretion history under the influence of stellar ionizing and dissociating UV feedback. Our coupled SE RHD calculations result in a wide diversity of final stellar masses covering 10 M-circle dot less than or similar to M-* less than or similar to 10(3) M-circle dot The formation of very massive (greater than or similar to 250 M-circle dot) stars is possible under weak UV feedback, whereas ordinary massive (a few x10 M-circle dot) stars form when UV feedback can efficiently halt the accretion. This may explain the peculiar abundance pattern of a Galactic metal-poor star recently reported by Aoki et al., possibly the observational signature of very massive precursor primordial stars. Weak UV feedback occurs in cases of variable accretion, in particular when repeated short accretion bursts temporarily exceed 0.01 M-circle dot yr(-1), causing the protostar to inflate. In the bloated state, the protostar has low surface temperature and UV feedback is suppressed until the star eventually contracts, on a thermal adjustment timescale, to create an H II region. If the delay time between successive accretion bursts is sufficiently short, the protostar remains bloated for extended periods, initiating at most only short periods of UV feedback. Disk fragmentation does not necessarily reduce the final stellar mass. Quite the contrary, we find that disk fragmentation enhances episodic accretion as many fragments migrate inward and are accreted onto the star, thus allowing continued stellar mass growth under conditions of intermittent UV feedback. This trend becomes more prominent as we improve the resolution of our simulations. We argue that simulations with significantly higher resolution than reported previously are needed to derive accurate gas mass accretion rates onto primordial protostars.

リンク情報
DOI
https://doi.org/10.3847/0004-637X/824/2/119
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000381912800055&DestApp=WOS_CPL
URL
http://orcid.org/0000-0003-3127-5982
ID情報
  • DOI : 10.3847/0004-637X/824/2/119
  • ISSN : 0004-637X
  • eISSN : 1538-4357
  • ORCIDのPut Code : 47771466
  • Web of Science ID : WOS:000381912800055
  • BibTex Code : 2016ApJ...824..119H

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