标题： 氦星供体通道用于Ia型超新星的前身星 显示英文标题

标题： Helium star donor channel for the progenitors of type Ia supernovae

摘要： Ia型超新星（SNe Ia）在天体物理学中扮演着重要角色，尤其是在宇宙演化研究中。近年来提出了几种SNe Ia的前身模型。 本文中，我们详细研究了氦星供体通道，在该通道中，碳氧白矮星（CO WD）从氦主序星或氦亚巨星吸积物质以增加其质量至钱德拉塞卡质量。 使用Eggleton的恒星演化代码，并假设光学厚风，同时采用Kato & Hachisu（2004）提出的氦壳层闪光到WDs的质量积累效率公式，我们对大约2600个紧密的WD双星系统进行了双星演化计算。 根据这些计算，我们在轨道周期-伴星质量（$\log P^{\rm i}-M^{\rm i}_2$）平面上绘制了不同WD质量下SNe Ia的初始参数图。 研究表明，氦星供体通道对于产生SNe Ia（即银河系中的$\sim 1.2\times10^{-3} {\rm yr}^{-1}$）值得注意，并且该通道的前身可能会表现为软X射线源。 重要的是，这个通道可以解释具有较短延迟时间（$\la 10^{8}$年）的SNe Ia，这与最近关于SNe Ia前身年轻群体的观测暗示是一致的。 显示英文摘要

摘要： Type Ia supernovae (SNe Ia) play an important role in astrophysics, especially in the study of cosmic evolution. There are several progenitor models for SNe Ia proposed in the past years. In this paper, we have carried out a detailed study of the He star donor channel, in which a carbon-oxygen white dwarf (CO WD) accretes material from a He main sequence star or a He subgiant to increase its mass to the Chandrasekhar mass. Employing Eggleton's stellar evolution code with an optically thick wind assumption, and adopting the prescription of Kato & Hachisu (2004) for the mass accumulation efficiency of the He-shell flashes onto the WDs, we performed binary evolution calculations for about 2600 close WD binary systems. According to these calculations, we mapped out the initial parameters for SNe Ia in the orbital period--secondary mass ($\log P^{\rm i}-M^{\rm i}_2$) plane for various WD masses from this channel. The study shows that the He star donor channel is noteworthy for producing SNe Ia (i.e. $\sim 1.2\times10^{-3} {\rm yr}^{-1}$ in the Galaxy), and that the progenitors from this channel may appear as supersoft X-ray sources. Importantly, this channel can explain SNe Ia with short delay times ($\la 10^{8}$ yr), which is consistent with recent observational implications of young populations of SN Ia progenitors.