标题： 氦核白矮星的共有包层演化 显示英文标题

标题： Post-common Envelope Evolution of Helium-core White Dwarfs

摘要： 氦核白矮星（He WDs）通过公共包层（CE）演化形成，为双星相互作用通道和致密遗迹的形成提供了宝贵的见解。 它们的冷却速率对近距双星中的可探测性和年龄估算至关重要。 与通过稳定洛希瓣溢出（SRLOF）形成的He WD相比，那些通过CE通道形成的He WD经历截然不同的质量损失历史，导致不同的后CE演化行为。 我们探讨了残余氢包层质量（Mh）如何影响CE He WD的冷却演化，重点研究了分岔点在设定Mh和允许残余氢燃烧中的作用。 使用LPCODE恒星演化代码，我们计算了从0.20到0.42倍太阳质量的He WD模型，从后CE条件演化到白矮星冷却轨迹。 出现了两条演化分支：（i）非闪焰序列，以极快的速度冷却且氢燃烧可以忽略不计；（ii）闪焰序列，在冷却之前氢壳层闪焰会改变包层结构。 对于有效温度在12,000到27,000 K之间的最小包层模型，在5到130百万年内冷却，并在较低温度下大约300百万年内达到稳定状态，比SRLOF对应的模型年轻得多。 相比之下，含有更多氢的模型保持活跃的核燃烧，延迟冷却并产生数十亿年的年龄。 闪焰序列延长了白矮星前阶段，尽管仍短于SRLOF演化。 Mh的值也会影响白矮星质量和表面重力的估计，相对于SRLOF白矮星引入系统性偏移。 我们的结果显示，CE He WD遵循不同的演化路径，这对解释宿主He WD的紧凑双星的性质和命运具有重要意义。 显示英文摘要

摘要： Helium-core white dwarfs (He WDs) formed through common envelope (CE) evolution offer valuable insight into binary interaction channels and compact remnant formation. Their cooling rates critically impact both detectability and age estimates in close binaries. Compared to He WDs formed via stable Roche-lobe overflow (SRLOF), those from the CE channel undergo markedly different mass-loss histories, resulting in distinct post-CE evolutionary behavior. We explore how the mass of the residual hydrogen envelope (Mh) shapes the cooling evolution of CE He WDs, focusing on the role of the bifurcation point in setting Mh and enabling residual hydrogen burning. Using the LPCODE stellar evolution code, we computed models of He WDs with masses from 0.20 to 0.42 solar masses, evolving from post-CE conditions to the white dwarf cooling track. Two evolutionary branches emerge: (i) non-flashing sequences, which cool rapidly with negligible hydrogen burning, and (ii) flashing sequences, where hydrogen shell flashes alter the envelope structure prior to cooling. Minimal-envelope models cool within 5-130 million years for effective temperatures between 12,000 and 27,000 K, and reach in approx. 300 million years at lower temperatures, remaining much younger than SRLOF counterparts. In contrast, models with more hydrogen retain active nuclear burning, delaying cooling and yielding ages of several billion years. Flashing sequences prolong the pre-white dwarf phase, though still shorter than in SRLOF evolution. The value of Mh also affects WD mass and surface gravity estimates, introducing systematic shifts with respect to SRLOF WDs. Our results show that CE He WDs follow distinct evolutionary paths, with important implications for interpreting the nature and fate of compact binaries hosting He WDs.