发表机构
Armagh Observatory; Queen’s University Belfast（阿马天文台; 贝尔法斯特女王大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过MESA模型对比L/M依赖与传统RSG质量损失公式，发现L/M公式导致失控包层剥离，使约20太阳质量恒星形成Wolf-Rayet星，并影响超新星前身星。
AI 中文摘要
红超巨星（RSGs）的质量损失机制目前尚不明确，恒星演化模型依赖于经验公式。近年来，人们提出了新的超强风质量损失理论，其中包括对$L/M$的依赖，这与传统RSG风公式仅基于$L$的表述不同。我们研究了对比性的RSG质量损失公式如何影响大质量恒星从RSG阶段开始的晚期演化。我们使用MESA构建了一系列质量范围为$10\\,{\rm M}_\odot - 40\\,{\rm M}_\odot$的恒星演化模型，采用了RSG \cite{VS23}的$L/M$公式和传统的质量损失公式。无论恒星包层的处理方式如何，我们发现对于一颗25$\\,{\rm M}_\odot$的恒星，由于$L/M$公式具有反质量依赖性，其质量损失率比传统公式高出一个数量级。由于RSG光度由核心质量决定，并且对当前恒星质量基本不敏感，这形成了一个正反馈回路，驱动了失控的包层剥离。因此，初始质量$M_{\rm init} \sim \\,20\\,{\rm M}_\odot$的恒星能够剥离其氢包层，形成经典Wolf-Rayet（WR）星。我们得出这一结论不仅基于它们在赫罗图（HRD）上的位置，还基于我们使用PoWR恒星大气模型计算出的预测发射线光谱。初始质量$M_{\rm init}<20\\,{\rm M}_\odot$的恒星无法完全剥离包层，这意味着它们在核心氦燃烧后会膨胀。在附录A中，我们提出了一个通用解析模型，表明失控剥离的趋势随着质量损失对质量的反比例标度强度的增加而迅速增强。我们的模型展示了进入黄超巨星和WR区域的一条可行的单星路径。完全和部分剥离的程度对超新星（SN）前身星有直接影响，包括部分剥离的IIb型超新星。
英文摘要
Mass-loss in red supergiants (RSGs) is poorly understood and stellar evolution models rely on empirical prescriptions. In recent years, new superwind mass-loss ideas, including an $L/M$ dependence have been proposed, unlike traditional RSG wind recipes which are formulated on a $L$ dependence alone. We investigate how contrasting RSG mass-loss prescriptions affect the late-time evolution of massive stars from their RSG phase onwards. We used MESA to create a series of stellar evolution models with masses ranging from $10\,{\rm M}_\odot - 40\,{\rm M}_\odot$, using the RSG \cite{VS23} $L/M$ recipe and traditional mass-loss prescriptions. Independent of the treatment of the stellar envelope, we find for a 25$\,{\rm M}_\odot$ star that the $L/M$ recipe reaches an order of magnitude higher mass-loss rate than traditional recipes due to its inverse mass dependence. As the RSG luminosity is set by the core mass and becomes largely insensitive to the current stellar mass, this creates a positive feedback loop driving runaway envelope stripping. Consequently, stars with an initial mass $M_{\rm init} \sim \,20\,{\rm M}_\odot$ are able to strip their hydrogen envelope and form classical Wolf-Rayet (WR) stars. We draw this conclusion not solely on the basis of their HRD location, but also on their predicted emission-line spectrum that we compute with the PoWR stellar atmosphere code. Stars with $M_{\rm init}<20\,{\rm M}_\odot$ do not fully strip, meaning they expand after core helium burning. In Appendix A we present a generic analytical model showing that the tendency for runaway stripping increases rapidly with the strength of the inverse mass-loss scaling with mass. Our models demonstrate a viable single-star pathway into the yellow supergiant and WR regimes. The amounts of full and partial stripping have a direct effect on supernova (SN) progenitors, including partially stripped type IIb SNe.
CommentsAccepted in A&A(24th September), 7 pages, 7 figures, 1 table
