Effects of turbulence and rotation on protostar formation as a precursor of massive black holes
Effects of turbulence and rotation on protostar formation as a precursor of massive black holes
复制标题
湍流和旋转对作为大质量黑洞前兆的原恒星形成的影响
DOI：
10.1051/0004-6361/201424658
复制
发表时间：
2014
影响因子：
6.5
通讯作者：
Bovino
中科院分区：
文献类型：
--
作者：
Van Borm;Bovino
第一个超大质量黑洞的种子可能是由于热的原始气体在104 K晕中的直接坍缩，形成超大质量或准恒星作为中间阶段。特别是，我们调查的湍流和旋转的气体云的碎裂行为的影响。我们实现这一目标，通过改变初始湍流和旋转velocity.MethodsWe进行了3D自适应网格细化模拟的分辨率为64细胞每牛仔裤长度使用ENZO代码，模拟形成的原恒星达到前所未有的高中心密度1021厘米-3和空间尺度的几个太阳半径。为了实现这一目标，我们采用了KROME包，以改善化学和热processs.ResultsWe的建模，模拟的气体云的物理性质变得相似的小尺度上，无论初始量的湍流和旋转。在达到最高级别的细化之后，模拟已经另外演化了~5次自由落体时间。在每次模拟结束时，都会形成一个半径为2 × 10-2AU、质量约为7 × 10- 2 M的单一束缚团块，标志着原恒星形成的开始。没有强烈的碎片观察到年底的模拟，无论初始量的湍流或旋转，和高吸积率的几个太阳质量，每年被发现。ConclusionsGiven这样高的吸积率，一个准星的105兆兆，预计将在105年内形成。
ContextThe seeds of the first supermassive black holes may have resulted from the direct collapse of hot primordial gas in ≳104K haloes, forming a supermassive or quasi-star as an intermediate stage.AimsWe explore the formation of a protostar resulting from the collapse of primordial gas in the presence of a strong Lyman-Werner radiation background. Particularly, we investigate the impact of turbulence and rotation on the fragmentation behaviour of the gas cloud. We accomplish this goal by varying the initial turbulent and rotational velocities.MethodsWe performed 3D adaptive mesh refinement simulations with a resolution of 64 cells per Jeans length using the ENZO code, simulating the formation of a protostar up to unprecedentedly high central densities of 1021cm-3and spatial scales of a few solar radii. To achieve this goal, we employed the KROME package to improve modelling of the chemical and thermal processes.ResultsWe find that the physical properties of the simulated gas clouds become similar on small scales, irrespective of the initial amount of turbulence and rotation. After the highest level of refinement was reached, the simulations have been evolved for an additional ~5 freefall times. A single bound clump with a radius of 2 × 10-2AU and a mass of ~7 × 10-2M⊙is formed at the end of each simulation, marking the onset of protostar formation. No strong fragmentation is observed by the end of the simulations, regardless of the initial amount of turbulence or rotation, and high accretion rates of a few solar masses per year are found.ConclusionsGiven such high accretion rates, a quasi-star of 105M⊙is expected to form within 105years.