论文标题
超质量氧气核心白色矮人的形成及其进化和脉动特性
The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
论文作者
论文摘要
(删节的摘要)我们探索了超质量的形成(M _ {\ rm WD} \ Gtrsim 1.05 M_ \ Sun $),碳氧气核心白矮星是由单个恒星进化而产生的。我们还研究了它们的进化和脉动特性,并将其与单祖星中碳燃烧以及二进制合并预测所产生的氧核心的超质量白色矮人的氧气进行了比较。我们考虑了两种单星演化方案,用于形成超质量碳氧气核心白色矮人,涉及在核心氦气燃烧后退化的核心旋转,并降低了巨大的渐近巨型巨型支流恒星的质量损失率。我们通过假设它们与合并后残留物的碳氧核心完全混合,将其与超质量白色矮人的预测进行比较,这是由两个相等的碳氧气核心白色矮人合并而产生的预测。所得的超质量碳氧气核心白色矮人的进化明显慢,其氧气蛋白含量明显慢。我们的研究强烈表明,由单个恒星进化的碳氧核形成了超质量的白色矮人。我们发现,这些白色矮人的进化和脉动特性都与氧气核心对应物的进化和脉动明显不同,而与具有双重脱位合并可能导致的碳氧核的白色矮人。最终可以用来辨别超质量白矮人的核心组成及其形成场景。
(Abridged abstract) We explore the formation of ultra-massive (M_{\rm WD} \gtrsim 1.05 M_\sun$), carbon-oxygen core white dwarfs resulting from single stellar evolution. We also study their evolutionary and pulsational properties and compare them with those of the ultra-massive white dwarfs with oxygen-neon cores resulting from carbon burning in single progenitor stars, and with binary merger predictions. We consider two single-star evolution scenarios for the formation of ultra-massive carbon-oxygen core white dwarfs that involve rotation of the degenerate core after core helium burning and reduced mass-loss rates in massive asymptotic giant-branch stars. We compare our findings with the predictions from ultra-massive white dwarfs resulting from the merger of two equal-mass carbon-oxygen core white dwarfs, by assuming complete mixing between them and a carbon-oxygen core for the merged remnant. The resulting ultra-massive carbon-oxygen core white dwarfs evolve markedly slower than their oxygen-neon counterparts. Our study strongly suggests the formation of ultra-massive white dwarfs with carbon-oxygen core from single stellar evolution. We find that both the evolutionary and pulsation properties of these white dwarfs are markedly different from those of their oxygen-neon core counterparts and from those white dwarfs with carbon-oxygen core that might result from double degenerate mergers. This can eventually be used to discern the core composition of ultra-massive white dwarfs and their formation scenario.