Convection reconciles the difference in efficiencies between low-mass and high-mass common envelopes
Convection reconciles the difference in efficiencies between low-mass and high-mass common envelopes
复制标题
对流调节了低质量和高质量普通包络线之间的效率差异
DOI：
10.1093/mnras/stac2300
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发表时间：
2022
影响因子：
4.8
通讯作者：
Nordhaus, J.
中科院分区：
文献类型：
--
作者：
Wilson, E. C.;Nordhaus, J.
引力波并合源的形成途径包括共同包络演化。对高质量后共包络双星的观测表明，在CE阶段向包络的能量转移必须是高效的。相比之下，低质量的后CE双星的观测表明，在CE阶段的能量转移必须是非常低效的。对流，一个存在于低质量和高质量恒星中的过程，自然解释了这种二分法。利用Wolf-Rayet双星的观测结果，我们研究了对流和辐射损失对预测的高质量共同包络的最终分离的影响。尽管在大质量恒星中有强烈的对流，但这种影响是最小的，因为在对流可以将释放的轨道能量输送到表面之前，轨道就已经衰减了。在低质量系统中，对流传输发生得比轨道衰变更快，使系统能够辐射冷却，从而降低效率。对流的列入再现低质量和高质量的双星观测，仍然是一个必要的成分，以确定共同的信封的结果。
The formation pathways for gravitational-wave merger sources are predicted to include common envelope (CE) evolution. Observations of high-mass post-common envelope binaries suggest that energy transfer to the envelope during the CE phase must be highly efficient. In contrast, observations of low-mass post-CE binaries indicate that energy transfer during the CE phase must be highly inefficient. Convection, a process present in low-mass and high-mass stars naturally explains this dichotomy. Using observations of Wolf–Rayet binaries, we study the effects of convection and radiative losses on the predicted final separations of high-mass common envelopes. Despite robust convection in massive stars, the effect is minimal as the orbit decays well before convection can transport the liberated orbital energy to the surface. In low-mass systems, convective transport occurs faster then the orbit decays, allowing the system to radiatively cool, thereby lowering the efficiency. The inclusion of convection reproduces observations of low-mass and high-mass binaries and remains a necessary ingredient for determining outcomes of common envelopes.