论文标题
凉爽超级巨人形成的临界金属性。 I.对恒星质量损失和反馈的影响
Critical Metallicity of Cool Supergiant Formation. I. Effects on Stellar Mass Loss and Feedback
论文作者
论文摘要
本文系统地研究了金属性与巨大恒星的质量损失之间的关系。我们执行一维恒星演化模拟，并建立$ \ sim $ 2000型号的网格，初始质量在11到60 $ m _ {\ odot} $之间，并且绝对金属金属$ z $在0.00001和0.02之间。稳态风，包括热主要风和凉爽的超级风，是我们模型中巨大恒星大量损失的主要驱动因素。我们计算每个模型恒星寿命的总质量损失。我们的结果揭示了$ z \ sim 10^{ - 3} $的关键金属性$ z _ {\ rm {c}} $，其中群众损失表现出戏剧性的跳跃。如果$ z> z _ {\ rm {c}} $，那么巨大的恒星倾向于演变成凉爽的超级巨人，并且强大的酷风是运行的。相反，如果$ z <z _ {\ rm {c}} $，大量恒星通常保持为蓝色的超级巨人，其中未激活凉风，质量损失通常很弱。此外，我们用Salpeter初始质量功能计算出$ 10^5 $ $ m _ {\ odot} $ Star群集的风反馈。风释放的动能不会在$ z {\ rm {c}} $下表现出任何明显的过渡，因为凉爽的超级风的风速很低，对动能的贡献很小。临界金属性的影响为早期宇宙中金属贫困恒星的命运带来了影响。
This paper systematically studies the relation between metallicity and mass loss of massive stars. We perform one-dimensional stellar evolution simulations and build a grid of $\sim$2000 models with initial masses ranging between 11 and 60 $M_{\odot}$ and absolute metallicities $Z$ between 0.00001 and 0.02. Steady-state winds, comprising hot main-sequence winds and cool supergiant winds, are the main drivers of the mass loss of massive stars in our models. We calculate the total mass loss over the stellar lifetime for each model. Our results reveal the existence of a critical metallicity $Z_{\rm{c}}$ at $Z \sim 10^{-3}$, where the mass loss exhibits a dramatic jump. If $Z>Z_{\rm{c}}$, massive stars tend to evolve into cool supergiants, and a robust cool wind is operational. In contrast, if $Z<Z_{\rm{c}}$, massive stars usually remain as blue supergiants, wherein the cool wind is not activated and the mass loss is generally weak. Moreover, we calculate the wind feedback in a $10^5$ $M_{\odot}$ star cluster with the Salpeter initial mass function. The kinetic energy released by winds does not exhibit any significant transition at $Z_{\rm{c}}$ because the wind velocity of a cool supergiant wind is low and contributes little to the kinetic energy. The effects of critical metallicity provide implications for the fates of metal-poor stars in the early universe.
