Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution
Primordial star formation under the influence of far ultraviolet radiation: 1540 cosmological haloes and the stellar mass distribution
复制标题
DOI：
10.1093/mnras/stv044
复制
发表时间：
2015-03-21
影响因子：
4.8
通讯作者：
Yorke, H. W.
中科院分区：
文献类型：
--
作者：
Hirano, S.;Hosokawa, T.;Yorke, H. W.
我们进行了大量的早期结构形成的宇宙学模拟，并遵循1540恒星形成的气体云的形成和演化，推导出原始恒星的质量分布。在我们的宇宙学模拟中，星星的形成以两个不同的星族为特征，即所谓的星族III。1星和原始恒星在远紫外线（FUV）辐射的影响下形成（星族III。2（D）星）。在这项工作中，我们确定恒星质量的恒星形成云的物理性质和/或来自附近的原始恒星的外部光解离强度的依赖关系，这是来自原恒星反馈的二维辐射流体动力学模拟的结果。Pop III恒星的特征质量在z = 25时只有几百个太阳质量，并且随着红移的减小，它会逐渐向更低的质量转移。在高红移z > 20时，大约一半的恒星形成气体云暴露在强烈的FUV辐射下，从而产生大质量的Pop III。2（D）星。然而，当典型的Pop III恒星质量较小，恒星之间的平均物理距离由于宇宙膨胀而变大时，附近Pop III恒星的局部FUV辐射在较低的红移处变得较弱。因此，在z < 20时，大部分原始气体云是Pop III的宿主。1星。当z小于或接近15时，Pop III.1恒星在相对较冷的气体云中形成，这是由于H-2和HD分子的有效辐射冷却;这类恒星的质量为几× 10 M圆点。由于恒星的演化和最终命运取决于恒星的质量，不同时期形成的Pop III星在早期宇宙中扮演着不同的角色。
We perform a large set of cosmological simulations of early structure formation and follow the formation and evolution of 1540 star-forming gas clouds to derive the mass distribution of primordial stars. The star formation in our cosmological simulations is characterized by two distinct populations, the so-called Population III. 1 stars and primordial stars formed under the influence of far-ultraviolet (FUV) radiation (Population III. 2(D) stars). In this work, we determine the stellar masses by using the dependences on the physical properties of star-forming cloud and/or the external photo-dissociating intensity from nearby primordial stars, which are derived from the results of 2D radiation hydrodynamic simulations of protostellar feedback. The characteristic mass of the Pop III stars is found to be a few hundred solarmasses at z similar to 25, and it gradually shifts to lower masses with decreasing redshift. At high redshifts z > 20, about half of the star-forming gas clouds are exposed to intense FUV radiation and thus give birth to massive Pop III. 2(D) stars. However, the local FUV radiation by nearby Pop III stars becomes weaker at lower redshifts, when typical Pop III stars have smaller masses and the mean physical separation between the stars becomes large owing to cosmic expansion. Therefore, at z < 20, a large fraction of the primordial gas clouds host Pop III. 1 stars. At z less than or similar to 15, the Pop III.1 stars are formed in relatively cool gas clouds due to efficient radiative cooling by H-2 and HD molecules; such stars have masses of a few x 10 M-circle dot. Since the stellar evolution and the final fate are determined by the stellar mass, Pop III stars formed at different epochs play different roles in the early universe.