arXiv 2202.046712022-02-09astro-ph.SRastro-ph.GAastro-ph.HE

Wolf-Rayet型质量损失的起源和影响

The origin and impact of Wolf-Rayet-type mass loss

Andreas A. C. Sander, Jorick S. Vink, Erin R. Higgins, Tomer Shenar, Wolf-Rainer Hamann, Helge Todt

备注：: 6 pages, 3 figures, to appear in the proceedings of IAUS 366 "The Origin of Outflows in Evolved Stars"
DOI：: 10.1017/S1743921322000400

摘要：

经典沃尔夫-拉叶（WR）星是大质量恒星演化后期的一个重要阶段。作为贫氢的大质量恒星，这些天体已经失去了它们的外层，同时仍然通过它们突出的发射线光谱表明的强风失去进一步的质量。沃尔夫-拉叶星已经在许多不同的星系中被探测到。它们的强风是恒星演化和星族合成模型的主要成分。然而，一个关于它们强烈质量损失的连贯的理论图景才刚刚开始出现。特别是，WR星的出现作为金属丰度（Z）的函数仍然远未被理解。为了揭示沃尔夫-拉叶星复杂而密集的风的性质，我们采用了新一代的模型大气，包括在不断扩大的非LTE情况下风流体动力学的一致解决方案。有了这项技术，我们可以剖析驱动风的成分，并预测氢耗尽的大质量恒星的质量损失。我们的建模工作揭示了一个复杂的图片与强大的，非线性的依赖关系的亮度质量比和Z与陡峭的，但不完全突然发病WR型风氦星。我们的研究结果，我们提供了一个理论上的动机，人口的氦星在低Z，这不能通过WR型光谱特征检测。我们的研究大规模氦星大气模型产生的第一个质量损失配方来自第一性原理在这个政权。在恒星演化模型中实现我们的第一个发现，我们展示了传统方法如何倾向于高估年轻宇宙中WR型质量损失。

英文摘要：

Classical Wolf-Rayet (WR) stars mark an important stage in the late evolution of massive stars. As hydrogen-poor massive stars, these objects have lost their outer layers, while still losing further mass through strong winds indicated by their prominent emission line spectra. Wolf-Rayet stars have been detected in a variety of different galaxies. Their strong winds are a major ingredient of stellar evolution and population synthesis models. Yet, a coherent theoretical picture of their strong mass-loss is only starting to emerge. In particular, the occurrence of WR stars as a function of metallicity (Z) is still far from being understood. To uncover the nature of the complex and dense winds of Wolf-Rayet stars, we employ a new generation of model atmospheres including a consistent solution of the wind hydrodynamics in an expanding non-LTE situation. With this technique, we can dissect the ingredients driving the wind and predict the resulting mass-loss for hydrogen-depleted massive stars. Our modelling efforts reveal a complex picture with strong, non-linear dependencies on the luminosity-to-mass ratio and Z with a steep, but not totally abrupt onset for WR-type winds in helium stars. With our findings, we provide a theoretical motivation for a population of helium stars at low Z, which cannot be detected via WR-type spectral features. Our study of massive He-star atmosphere models yields the very first mass-loss recipe derived from first principles in this regime. Implementing our first findings in stellar evolution models, we demonstrate how traditional approaches tend to overpredict WR-type mass loss in the young Universe.

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。

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