2020MNRAS.497..829F -
Mon. Not. R. Astron. Soc., 497, 829-845 (2020/September-1)
Formation of massive stars under protostellar radiation feedback: very metal-poor stars.
FUKUSHIMA H., HOSOKAWA T., CHIAKI G., OMUKAI K., YOSHIDA N. and KUIPER R.
Abstract (from CDS):
We study the formation of very metal-poor stars under protostellar radiative feedback effect. We use cosmological simulations to identify low-mass dark matter haloes and star-forming gas clouds within them. We then follow protostar formation and the subsequent long-term mass accretion phase of over one million years using two-dimensional radiation-hydrodynamics simulations. We show that the critical physical process that sets the final mass is the formation and expansion of a bipolar H II region. The process is similar to the formation of massive primordial stars, but radiation pressure exerted on dust grains also contributes to halting the accretion flow in the low-metallicity case. We find that the net feedback effect in the case with metallicity Z = 10–2 Z☉ is stronger than in the case with Z ∼ 1 Z☉. With decreasing metallicity, the radiation-pressure effect becomes weaker, but photoionization heating of the circumstellar gas is more efficient owing to the reduced dust attenuation. In the case with Z = 10–2 Z☉, the central star grows as massive as 200 solar masses, similarly to the case of primordial star formation. We conclude that metal-poor stars with a few hundred solar masses can be formed by gas accretion despite the strong radiative feedback.
Abstract Copyright:
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
accretion, accretion discs - stars: formation - stars: massive - stars: Population II - cosmology: theory
Simbad objects:
1
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