论文标题
氦核闪光灯的呼吸症特征
Asteroseismic signatures of the helium-core flash
论文作者
论文摘要
所有演变的带有质量的星星$ m_ \ star \ lyssim 2m_ \ odot $在他们的第一阶段结束时以巨大的明星的身份在第一阶段结束时进行氦气闪光灯。尽管从理论上预测了50多年前，但这种核心闪存阶段尚未观察到。我们在这里表明，通过He-Flash驱动的对流对重力模式（G模式）随机激发，能够到达恒星表面，并在热量沃尔夫恒星中诱导具有几个mmag顺序的热量符号变化。因此，现在可以通过相对明亮的恒星中的过渡系外行星调查卫星（例如幅度$ i_c \ lyssim 13 $）来检测它们。预测周期的范围从几千秒到数万秒，具体取决于激发区域的细节。此外，我们发现随机激发的脉动再现了在几个富含他的热量热的恒星中观察到的脉动。这些明星，尤其是未来的苔丝目标Feige 46，是首次探究He-Core Flash的最有前途的候选人。
All evolved stars with masses $M_\star\lesssim 2M_\odot$ undergo a helium(He)-core flash at the end of their first stage as a giant star. Although theoretically predicted more than 50 years ago, this core-flash phase has yet to be observationally probed. We show here that gravity modes (g modes) stochastically excited by He-flash driven convection are able to reach the stellar surface, and induce periodic photometric variabilities in hot-subdwarf stars with amplitudes of the order of a few mmag. As such they can now be detected by space-based photometry with the Transiting Exoplanet Survey Satellite (TESS) in relatively bright stars (e.g. magnitudes $I_C\lesssim 13$). The range of predicted periods spans from a few thousand seconds to tens of thousand seconds, depending on the details of the excitation region. In addition, we find that stochastically excited pulsations reproduce the pulsations observed in a couple of He-rich hot subdwarf stars. These stars, and in particular the future TESS target Feige 46, are the most promising candidates to probe the He-core flash for the first time.
