标题： 围绕参宿星的星际介质的数值模型 显示英文标题

标题： Numerical models for the circumstellar medium around Betelgeuse

摘要： 附近的红超巨星（RSG）参宿七在其表面至少0.5秒差距的范围内有一个复杂的星际介质，其形状由过去0.1百万年内的质量损失历史、其环境以及它在星际介质（ISM）中的运动所决定。原则上，可以通过将流体动力学模型与观测结果进行比较来约束其质量损失历史。观测和数值模拟表明，参宿七有一个非常年轻的弓形激波，因此这颗恒星可能只是最近才成为RSG。为了测试这种可能性，我们计算了一个与参宿七特性一致的单星恒星演化模型。我们将所得的演化恒星风纳入二维流体动力学模拟中，以模拟一颗正在生命末期过渡为RSG的逃逸蓝超巨星（BSG）。坍缩的BSG风泡会引发一个弓形激波状的内壳，至少在表面上看起来类似于参宿七的弓形激波，并且具有相似的质量。围绕这个内壳的是由现已停止的BSG风与ISM相互作用产生的更大尺度的退行性弓形激波。我们研究了这个外层壳是否可以解释位于参宿七弓形激波前方（至少在投影上）的条状特征。 显示英文摘要

摘要： The nearby red supergiant (RSG) Betelgeuse has a complex circumstellar medium out to at least 0.5 parsecs from its surface, shaped by its mass-loss history within the past 0.1 Myr, its environment, and its motion through the interstellar medium (ISM). In principle its mass-loss history can be constrained by comparing hydrodynamic models with observations. Observations and numerical simulations indicate that Betelgeuse has a very young bow shock, hence the star may have only recently become a RSG. To test this possibility we calculated a stellar evolution model for a single star with properties consistent with Betelgeuse. We incorporated the resulting evolving stellar wind into 2D hydrodynamic simulations to model a runaway blue supergiant (BSG) undergoing the transition to a RSG near the end of its life. The collapsing BSG wind bubble induces a bow shock-shaped inner shell which at least superficially resembles Betelgeuse's bow shock, and has a similar mass. Surrounding this is the larger-scale retreating bow shock generated by the now defunct BSG wind's interaction with the ISM. We investigate whether this outer shell could explain the bar feature located (at least in projection) just in front of Betelgeuse's bow shock.