论文标题
应对损失：从后序列供体星中传质的稳定性
Coping with loss: Stability of mass transfer from post-main sequence donor stars
论文作者
论文摘要
传质的稳定性对于确定通向各种紧凑型二进制的途径至关重要，例如紧凑的主序列白矮人的二进制二进制组，以及瞬态，例如双白色矮人合并和发光的红色novae。尽管它的重要性，但仅存在很少的系统研究传质的稳定性。使用1D恒星进化代码MESA，我们研究了在二进制文件中质量损失的质量损失后序列供体星，其质量在$ 1 m _ {\ odot} $和$ 8 m _ {\ odot} $之间，而无需假设捐助者对捐助者的质量损失对质量损失做出反应。我们将增生物视为一个点质量，我们不进化，并假设传质是保守的。我们发现，最能预测失控传质开始的标准是基于向质量损失有效绝热供体反应的过渡。 We find that the critical mass ratio $q_{\rm qad} \sim 0.25$ for stars crossing the Hertzsprung gap, while for convective giants $q_{\rm qad}$ decreases from $\sim 1$ at the base of the RGB to $\sim 0.1$ at the the onset of thermal pulses on the AGB.供体恒星的有效绝热响应仅在红色巨人的最外层局部最外层的局部热时间尺度上以非常高的临界质量转移速率发生。对于$ q> q _ {\ rm qAD} $是自我调节的，但是对于进化的巨人来说，所得的质量转移速率可能很高，以至于进化变得动态性和/或捐赠者可以溢出其外叶。我们的结果表明，与快速二元种群合成中通常假设的二元参数空间相比，传质是稳定的，并且在最近的类似研究中发现。此外，我们发现临界质量比对供体恒星质量和半径的系统依赖性可能会对后质量转移人群的预测产生重大影响。
The stability of mass transfer is critical in determining pathways towards various kinds of compact binaries, such as compact main-sequence white-dwarf binaries, and transients, such as double white-dwarf mergers and luminous red novae. Despite its importance, only very few systematic studies of the stability of mass transfer exist. Using the 1D stellar evolution code MESA, we study the behaviour of mass-losing post-main-sequence donor stars with masses between $1 M_{\odot}$ and $8 M_{\odot}$ in binaries, without assuming that the donor star responds to mass loss adiabatically . We treat the accretor as a point mass, which we do not evolve, and assume the mass transfer is conservative. We find that the criterion that best predicts the onset of runaway mass transfer is based on the transition to an effectively adiabatic donor response to mass loss. We find that the critical mass ratio $q_{\rm qad} \sim 0.25$ for stars crossing the Hertzsprung gap, while for convective giants $q_{\rm qad}$ decreases from $\sim 1$ at the base of the RGB to $\sim 0.1$ at the the onset of thermal pulses on the AGB. An effectively adiabatic response of the donor star only occurs at a very high critical mass-transfer rate due to the short local thermal timescale in the outermost layers of a red giant. For $q > q_{\rm qad}$ mass transfer is self-regulated, but for evolved giants the resulting mass-transfer rates can be so high that the evolution becomes dynamical and/or the donor can overflow its outer lobe. Our results indicate that mass transfer is stable for a wider range of binary parameter space than typically assumed in rapid binary population synthesis and found in recent similar studies. Moreover, we find a systematic dependence of the critical mass ratio on the donor star mass and radius which may have significant consequences for predictions of post-mass-transfer populations.
