The excitation of g-mode pulsations in hot helium-rich subdwarfs
The excitation of g-mode pulsations in hot helium-rich subdwarfs
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DOI：
10.1093/mnras/sty2763
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发表时间：
2018-10
影响因子：
4.8
通讯作者：
H. Saio;C. Jeffery
中科院分区：
文献类型：
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作者：
H. Saio;C. Jeffery
到目前为止，在富含氦的热亚矮星LS IV−14°116中激发g模脉动的驱动机制被证明是难以捉摸的。迄今为止，只有ε机制提供了部分解决方案。我们证明了质量为0.5的碳增强氦主序星模型在与观测结果相匹配的正确周期范围内对g模脉动是不稳定的，并且这些脉动是由碳和氧不透明度在106 K左右的颠簸驱动的κ机制激发的。因此，富含氦的热亚矮星变星代表了GW Vir变星的低温延伸。如果在核心氦基本耗尽后，2氦星星的质量迅速损失，那么所需的碳富集可以得到解释，这可能是某些双星相互作用的结果。
The driving mechanism responsible for exciting g-mode pulsations in the helium-rich hot subdwarf LS IV−14°116 has, so far, proved elusive. To date, only the ε-mechanism has offered a partial solution. We demonstrate that models of carbon-enhanced helium main-sequence stars having a mass of 0.5are unstable to g-mode pulsations in exactly the right period range to match the observations, and that these pulsations are excited by the κ-mechanism driven by carbon- and oxygen opacity bumps at around 106K. Helium-rich hot subdwarf pulsators therefore represent a low-temperature extension of the GW Vir variables. The required carbon enrichment can be explained if rapid mass-loss from a 2helium star occurs after core helium has been substantially depleted, presumably as a consequence of some binary interaction.