论文标题
在原恒星辐射反馈下形成巨大的恒星：非常金属贫困的星星
Formation of massive stars under protostellar radiation feedback: Very metal-poor stars
论文作者
论文摘要
我们研究了在原始的辐射反馈效果下形成非常贫穷的恒星。我们使用宇宙学模拟来识别其中的低质量暗物质光环和恒星形成的气云。然后，使用二维辐射流动力学模拟，我们遵循原始的形成和随后的长期质量积聚阶段。我们表明，设定最终质量的关键物理过程是双相HII区域的形成和扩展。该过程类似于大规模原始恒星的形成，但是在灰尘晶粒上施加的辐射压力也有助于停止在低金属性情况下的吸积流。我们发现具有金属性的净反馈效果$ z = 10^{ - 2} 〜z _ {\ odot} $比$ z \ sim 1〜z _ {\ odot} $强。随着金属性的降低，辐射压力效应变得较弱，但是由于灰尘衰减的减少，偶然气体的光电离电加热更有效。在$ z = 10^{ - 2} 〜z _ {\ odot} $的情况下，中央恒星的增长与200个太阳质量一样大，类似于原始恒星形成的情况。我们得出的结论是，尽管有强烈的辐射反馈，但可以通过气体积聚形成几百个太阳能的金属贫困恒星。
We study the formation of very metal-poor stars under protostellar radiative feedback effect. We use cosmological simulations to identify low-mass dark matter halos 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 formation and expansion of a bipolar HII 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 $Z = 10^{-2}~Z_{\odot}$ is stronger than in the case with $Z \sim 1~Z_{\odot}$. 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 $Z = 10^{-2}~Z_{\odot}$, 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.
