第一颗恒星：双星和小型多重系统的形成
The first stars: formation of binaries and small multiple systems
摘要：
我们调查的形成无金属，人口III（Pop III），恒星在一个minihalo在z ~ 20的平滑粒子流体动力学（SPH）模拟，从宇宙学的初始条件。采用分层放大的方法，我们获得了足够的数值分辨率，可以跟踪小晕中心的坍缩气体，直到数密度达到10^12 cm^-3。这使我们能够研究原恒星吸积到最初的流体静力学核心，我们表示为一个不断增长的汇粒子，在改进的物理细节。吸积过程，特别是它的终止，决定了第一批恒星达到的最终质量。原始初始质量函数（IMF）反过来在确定第一批恒星在多大程度上推动了早期宇宙演化方面发挥了重要作用。我们继续我们的模拟5000年后，第一个汇粒子已经形成。在此期间，一个圆盘状的结构围绕着第一颗原恒星组装。这个盘在重力作用下不稳定，形成明显的螺旋结构，并分裂成其他几个原恒星种子。在模拟结束时，一个小的多重系统已经形成，主要是一个质量为~ 40 M_Sun和~ 10 M_Sun的双星。如果Pop III恒星通常以双星或小倍数的形式形成，那么原始恒星形成的标准模型（其中单个孤立恒星被预测形成迷你晕）将不得不被修改。这将对第一批恒星的观测特征产生至关重要的影响，例如它们的核合成模式，以及可能的Pop III黑洞双星的引力波发射。
英文摘要：
We investigate the formation of metal-free, Population III (Pop III), stars within a minihalo at z ~ 20 with a smoothed particle hydrodynamics (SPH) simulation, starting from cosmological initial conditions. Employing a hierarchical, zoom-in procedure, we achieve sufficient numerical resolution to follow the collapsing gas in the center of the minihalo up to number densities of 10^12 cm^-3. This allows us to study the protostellar accretion onto the initial hydrostatic core, which we represent as a growing sink particle, in improved physical detail. The accretion process, and in particular its termination, governs the final masses that were reached by the first stars. The primordial initial mass function (IMF), in turn, played an important role in determining to what extent the first stars drove early cosmic evolution. We continue our simulation for 5000 yr after the first sink particle has formed. During this time period, a disk-like configuration is assembled around the first protostar. The disk is gravitationally unstable, develops a pronounced spiral structure, and fragments into several other protostellar seeds. At the end of the simulation, a small multiple system has formed, dominated by a binary with masses ~ 40 M_Sun and ~ 10 M_Sun. If Pop III stars were to form typically in binaries or small multiples, the standard model of primordial star formation, where single, isolated stars are predicted to form in minihaloes, would have to be modified. This would have crucial consequences for the observational signature of the first stars, such as their nucleosynthetic pattern, and the gravitational-wave emission from possible Pop III black-hole binaries.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
