论文标题
传质稳定标准对双白矮人种群的影响
Influence of a mass transfer stability criterion on double white dwarf populations
论文作者
论文摘要
传质稳定性是二进制进化中的重要问题。 GE等。研究了通过建立绝热质量损失模型动态稳定质量转移的临界质量比，发现巨型分支上的供体恒星往往比基于复合多层恒星模型的供体恒星更稳定。我们将研究传质稳定性对DWD种群形成和特性的影响。我们进行了一系列二元种群的综合，其中分别采用了绝热质量损失模型（GE的模型）的临界质量比，并分别采用了复合材料的多面年模型。对于GE的模型，大多数DWD都是由稳定的非保守的Roche Lobe溢出以及COS射出效率$α_{CE} $的稳定的Roche Lobe Overflow（CE）弹出通道（CE）弹出通道（RL+CE通道）产生的。而多面年模型的结果在很大程度上取决于$α_{ce} $的所采用值。我们发现从RL+CE通道产生的DWD具有可比的WD质量，质量比分布峰值约为1。根据DWD的幅度限制样本，可检测到的DWD的空间密度以及GE的型号非常低的WD（ELM WD）伴侣的型号的含量为1347 $ 1347 $和473 kpc^$ cobs^$ cobs^$ cobs，而多面年模型预测DWD的空间密度约为2-3美元。我们还发现，GE模型中DWD合并速率分布的结果比多趋于模型的观测值更好，并且在银河系中与ELM WD同伴的合并率约为$ 1.8 \ times 10^{ - 3} yr^{-1} yr^{ - 1} $在GE的模型中，这是可比较的观察估计。我们确认，传质稳定性在DWD种群的形成和特性，然后在SNE IA和可检测的GW来源的祖细胞中起着重要作用。
Mass transfer stability is an essential issue in binary evolution. Ge et al. studied critical mass ratios for dynamically stable mass transfer by establishing adiabatic mass loss model and found that the donor stars on the giant branches tend to be more stable than that based on the composite polytropic stellar model. We would investigate the influence of mass transfer stability on the formation and properties of DWD populations. We performed a series of binary population synthesis, where the critical mass ratios from adiabatic mass loss model (Ge's model) and that from the composite polytropic model are adopted, respectively. For Ge's model, most of the DWDs are produced from the stable non-conservative Roche lobe overflow plus common envelope (CE) ejection channel (RL+CE channel) regardless of the CE ejection efficiency $α_{CE}$. While the results of the polytropic model strongly depend on the adopted value of $α_{ CE}$. We find DWDs produced from the RL+CE channel have comparable WD masses and the mass ratio distribution peaks at around 1. Based on the magnitude-limited sample of DWDs, the space densities for the detectable DWDs and those with extremely low-mass WD (ELM WD) companions in Ge's model is $1347$ and $473 kpc^{-3}$, respectively, close to observations. While the polytropic model overpredicts space density of DWDs by a factor of about $2-3$. We also find that the results of DWD merger rate distribution in Ge's model reproduce the observations better than that of the polytropic model, and the merger rate of DWDs with ELM WD companions in the Galaxy is about $1.8\times 10^{-3} yr^{-1}$ in Ge's model, which is comparable to the observation estimation. We confirm that the mass transfer stability plays important roles in the formation and properties of DWD populations, and then in the progenitors of SNe Ia and detectable GW sources.
