Self-consistent atmospheric models of very massive stars and their early evolution in dense stellar systems

大质量恒星的自洽大气模型及其在这些恒星系统中的早期演化

• 批准号: 246058756
• 负责人: Professor Dr. Adalbert Wilhelm Alois Pauldrach (†)
• 金额: --
• 依托单位: Department of Astronomy and Astrophysics
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/246058756?language=en
• 关键词: Self; consistent; atmospheric; models; very

The evolution of the dense cores of massive starburst clusters is affected by dynamical processes induced by N-body interactions. The resultant formation, via mergers, of very massive stars with masses up to several 1000 solar masses may be essential for the evolution of galaxies and decisive for the evolution of such clusters. For example, evidence has been collected that young dense clusters in galactic bulges harbor intermediate-mass black holes (IMBHs) with masses up to several 1000 solar masses; these objects could provide important clues for understanding the formation of supermassive black holes (SMBHs) in galactic centers.The evolution of such very massive stars (VMSs) is significantly influenced by their pronounced stellar winds, and the further evolution of merger products depends critically on their mass loss rates. The determination of the mass loss rates, however, requires a highly consistent treatment of the physical state of the outflowing gas and of the hydrodynamic and radiative processes in the expanding atmospheres.In preliminary prior work we have already combined consistent models of expanding atmospheres with stellar evolutionary calculations of VMSs for the purpose of modelling the evolution of dense stellar clusters. As suspected, the computed mass loss rates, terminal wind velocities, and spectral energy distributions revealed important implications for stellar evolutionary calculations. Solar-metallicity stars, for instance, were shown to have high mass-loss rates, but presumably not so high as to exclude VMSs, formed by dynamical processes in dense clusters, from ending their life massive enough to form IMBHs.The primary objective of the present proposal is to develop an advanced diagnostic method of O-type stellar atmospheres, including an assessment of the accuracy of the determinations of abundances, stellar and wind parameters by means of detailed interpretations of observational results; as a central task, mass loss rates of VMSs for different compositions will be computed with an improved level of consistency. The basic parameters deduced from these computations will be used for comparisons with present predictions from the evolution of very massive stars, and we will focus on the importance of the improved mass loss rates for the formation of IMBHs.

大质量星暴星团致密核的演化受到N体相互作用引起的动力学过程的影响。由此形成的，通过合并，质量高达几千个太阳质量的非常大的恒星可能是必不可少的星系的演化和决定性的演化这样的集群。例如，已经收集到的证据表明，银河系凸起中的年轻致密星团中存在质量高达数千个太阳质量的中等质量黑洞（IMBH）;这些天体可以为理解银河系中心超大质量黑洞（SMBH）的形成提供重要线索。2这种超大质量恒星（VMS）的演化受到其明显的恒星风的显著影响，并且合并产物的进一步演变关键取决于它们的质量损失率。的质量损失率的测定，但是，需要一个高度一致的处理的物理状态的流出的气体和流体动力学和辐射过程中的膨胀atmossian.In初步的工作，我们已经结合一致的模型膨胀的大气与恒星的演化计算VMSs为目的的模拟致密星团的演化。正如所怀疑的那样，计算出的质量损失率，终端风速和光谱能量分布揭示了恒星演化计算的重要意义。例如，太阳金属丰度恒星的质量损失率很高，但可能不会高到排除VMS的程度，VMS是在致密星团中通过动力学过程形成的，其质量足以形成IMBHs。本提案的主要目标是发展一种先进的O型恒星大气诊断方法，包括评估丰度测定的准确性，通过对观测结果的详细解释来确定恒星和风参数;作为一项中心任务，将以更高的一致性计算不同组成的VMS的质量损失率。从这些计算中推导出的基本参数将用于与目前的预测非常大质量的恒星的演化进行比较，我们将专注于改进的质量损失率的重要性，形成IMBHs。

项目成果

Spitzer observations of extragalactic H II regions - III. NGC 6822 and the hot star, H II region connection

斯皮策对河外 H II 区域的观测 - III NGC 6822 和热星、H II 区域的连接

• DOI: 10.1093/mnras/stw719
• 发表时间: 2016
• 期刊: Monthly Notices of the Royal Astronomical Society
• 影响因子: 4.8
• 作者: R. H. Rubin;J. P. Simpson;S. W. J. Colgan;R. J. Dufour;J. Kader;I. A. McNabb;A. W. A. Pauldrach;J. A. Weber
• 通讯作者: J. A. Weber