The mass-loss rates of massive helium stars are one of the major uncertainties in modern astrophysics. Regardless of whether they were stripped by a binary companion or managed to peel off their outer layers by themselves, the influence and final fate of helium stars -- in particular the resulting black hole mass -- highly depends on their wind mass loss as stripped-envelope objects. While empirical mass-loss constraints for massive helium stars have improved over the last decades, the resulting recipes are limited to metallicities with the observational ability to sufficiently resolve individual stars. Yet, theoretical efforts have been hampered by the complexity of Wolf-Rayet (WR) winds arising from the more massive helium stars. In an unprecedented effort, we calculate next-generation stellar atmosphere models resembling massive helium main sequence stars with Fe-bump driven winds up to $500\,M_\odot$ over a wide metallicity range between $2.0$ and $0.02\,Z_\odot$. We uncover a complex $\Gamma_\text{e}$-dependency of WR-type winds and their metallicity-dependent breakdown. The latter can be related to the onset of multiple scattering, requiring higher $L/M$-ratios at lower metallicity. Based on our findings, we derive the first ever theoretically-motivated mass-loss recipe for massive helium stars. We also provide estimates for LyC and He II ionizing fluxes, finding stripped helium stars to contribute considerably at low metallicity. In sharp contrast to OB-star winds, the mass loss for helium stars scales with the terminal velocity. While limited to the helium main sequence, our study marks a major step towards a better theoretical understanding of helium star evolution.

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关于大质量氦星风和沃尔夫-拉叶型质量损失的性质

大质量氦星的质量损失率是现代天体物理学中的主要不确定因素之一。无论它们是被双星伴星剥离还是设法自行剥离外层，氦星的影响和最终命运——尤其是由此产生的黑洞质量——在很大程度上取决于它们剥离时的风质量损失——信封对象。虽然在过去的几十年里，对大质量氦星的经验质量损失约束有所改善，但由此产生的配方仅限于具有足够分辨单个恒星的观测能力的金属丰度。然而，理论工作受到了由更大质量的氦星引起的沃尔夫-拉叶 (WR) 风的复杂性的阻碍。以前所未有的努力，我们计算了类似于大质量氦主序星的下一代恒星大气模型，在 $2.0$ 和 $0.02\,Z_\odot$ 之间的广泛金属丰度范围内，Fe-bump 驱动的风高达 $500\,M_\odot$。我们发现了 WR 型风的复杂的 $\Gamma_\text{e}$ 依赖性及其与金属量相关的分解。后者可能与多重散射的开始有关，在较低的金属丰度下需要较高的 $L/M$ 比率。根据我们的发现，我们推导出了第一个理论上为大质量氦星提供的质量损失配方。我们还提供了 LyC 和 He II 电离通量的估计值，发现剥离的氦星在低金属丰度时贡献很大。与 OB 星风形成鲜明对比的是，氦星的质量损失与终端速度成比例。虽然仅限于氦主序，