Massive stars have strong stellar winds that direct their evolution through the upper Hertzsprung–Russell diagram and determine the black hole mass function. Furthermore, wind strength dictates the atmospheric structure that sets the ionizing flux. Finally, the wind directly intervenes with the stellar envelope structure, which is decisive for both single-star and binary evolution, affecting predictions for gravitational wave events. Key findings of current hot star research include: ▪ The traditional line-driven wind theory is being updated with Monte Carlo and comoving frame computations, revealing a rich multivariate behavior of the mass-loss rate [Formula: see text] in terms of M, L, Eddington Γ, Teff, and chemical composition Z. Concerning the latter, [Formula: see text] is shown to depend on the iron (Fe) opacity, making Wolf–Rayet populations, and gravitational wave events dependent on host galaxy Z. ▪ On top of smooth mass-loss behavior, there are several transitions in the Hertzsprung–Russell diagram, involving bistability jumps around Fe recombination temperatures, leading to quasi-stationary episodic, and not necessarily eruptive, luminous blue variable and pre-SN mass loss. ▪ Furthermore, there are kinks. At 100 [Formula: see text] a high Γ mass-loss transition implies that hydrogen-rich, very massive stars have higher mass-loss rates than commonly considered. At the other end of the mass spectrum, low-mass stripped helium stars no longer appear as Wolf–Rayet stars but as optically thin stars. These stripped stars, in addition to very massive stars, are two newly identified sources of ionizing radiation that could play a key role in local star formation as well as at high redshift.

中文翻译：

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热星质量损失的理论与诊断


大质量恒星具有强大的恒星风，这些风通过上赫兹普龙-罗素图引导它们的演化，并决定了黑洞的质量函数。此外，风力强度决定了设置电离通量的大气结构。最后，风直接干预恒星包络结构，这对单星和双星演化都起着决定性作用，影响了引力波事件的预测。当前热星研究的主要发现包括：▪传统的线驱动风理论正在通过蒙特卡洛和共动框架计算进行更新，揭示了质量损失率 [公式：见正文] 在 M、L、Eddington Γ、Teff 和化学成分 Z 方面的丰富多变量行为。关于后者，[公式：见正文] 显示取决于铁 （Fe） 的不透明度， 使 Wolf-Rayet 种群和引力波事件依赖于宿主星系 Z。▪除了平滑的质量损失行为之外，Hertzsprung-Russell 图中还有几个转变，涉及围绕 Fe 复合温度的双稳态跳跃，导致准平稳的偶发性，不一定是喷发的发光蓝色变星和 pre-SN 质量损失。▪ 此外，还有扭结。在 100 [公式：见正文] 时，高Γ质量损失转变意味着富含氢的超大质量恒星的质量损失率高于通常认为的。在质谱的另一端，低质量剥离的氦星不再表现为 Wolf-Rayet 星，而是光学薄星。除了大质量恒星之外，这些剥离的恒星是两个新发现的电离辐射源，可能在局部恒星形成以及高红移中发挥关键作用。