发表机构
Armagh Observatory and Planetarium; Zentrum für Astronomie der Universität Heidelberg, Astronomisches Rechen-Institut; Interdisziplinäres Zentrum für Wissenschaftliches Rechnen, Universität Heidelberg（阿马天文台和天文馆; 海德堡大学天文中心，天文计算研究所; 海德堡大学跨学科科学计算中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究针对太阳金属丰度下16-500倍太阳质量的极高质量恒星，利用PoWR-HD代码构建流体动力学星风模型，推导含拐点与双稳态行为的质量损失公式，其结果与观测吻合，可用于恒星演化计算。
AI 中文摘要
极高质量恒星的演化路径与最终命运主要由辐射驱动星风造成的质量损失决定。我们提出了一种针对（极）高质量恒星的新理论质量损失公式，该公式捕捉了其对爱丁顿参数Γ_e、光度、温度和氢丰度的复杂依赖关系。我们使用PoWR-HD代码，在非局部热力学平衡条件下计算了178个流体动力学自洽的星风-大气模型的广泛网格，自洽地预测了质量损失率和终端速度等星风属性。该网格覆盖的恒星质量M_*范围为16-500倍太阳质量，光度log(L_*/L_⊙)范围为5.5-6.8，内边界温度T_*范围为12-50千开尔文，氢质量分数X范围为0.01-0.9，金属丰度固定为Z=0.02。我们确认了在探索的参数空间内，M-Γ_e关系中存在质量损失拐点，该拐点标志着从低Γ_e时光学薄O型星风的浅标度（约2.8）向高Γ_e时光学厚星风的更陡标度（约10）的转变。我们推导了综合拟合关系，既捕捉了拐点行为，也捕捉了铁电离变化产生的两个双稳态跃变，并提供了用于恒星演化计算的辅助关系。我们的公式正确再现了拱门星团中与模型无关的过渡质量损失率，证实了我们在O型星到WNh型星过渡处预测率的准确性。将我们的公式应用于零龄主序，与最近在宽温度和爱丁顿参数范围内获得的经验M-Γ_e关系吻合极好。我们提供了一种基于物理、连续且经经验验证的（极）高质量恒星质量损失公式，适用于20-500倍太阳质量范围内的恒星演化计算。
英文摘要
The evolutionary pathways and ultimate fates of very massive stars are governed primarily by mass loss through radiatively driven winds. We present a new theoretical mass-loss prescription for (very) massive stars, capturing the complex dependence on the Eddington parameter $Γ_e$, luminosity, temperature, and hydrogen abundance. We calculated an extensive grid of 178 hydrodynamically self-consistent wind-atmosphere models in non-local thermodynamic equilibrium using the PoWR-HD code, predicting wind properties such as the mass-loss rate and terminal velocity self-consistently. The grid spans masses $M_*$ = 16-500 Msun, luminosities $\log(L_*/L_\odot) = 5.5-6.8$, inner boundary temperatures $T_* = 12-50$ kK, and hydrogen mass fractions X = 0.01-0.9, at a fixed metallicity Z=0.02. We confirm the presence of a mass-loss kink in the $\dot{M}-Γ_e$ relation across the explored parameter space. The kink marks the transition from a shallow scaling ($\sim 2$) at low $Γ_\mathrm{e}$ for optically thin O-star winds to a steeper scaling ($\sim 10$) for optically thick winds at high $Γ_e$. We derive comprehensive fitting relations capturing both the kink behaviour and two bistability jumps arising from iron ionisation changes, and provide auxiliary relations for implementation into stellar evolutionary calculations. Our prescription correctly reproduces the model-independent transition mass-loss rate in the Arches Cluster, confirming the accuracy of our predicted rates at the O-to-WNh transition. Application of our recipe to the zero-age main sequence provides excellent agreement with recent empirical $\dot{M}-Γ_e$ relations obtained for a wide range of temperatures and Eddington parameters. We provide a physically motivated, continuous, and empirically anchored mass-loss recipe for (very) massive stars, suitable for stellar evolution calculations in the 20-500 Msun range.
CommentsIncluded proof corrections. Accepted in A&A (30th July), 12 pages, 12 figures, 3 tables, 3 appendices
