The Properties of Fast Yellow Pulsating Supergiants: FYPS Point the Way to Missing Red Supergiants
The Properties of Fast Yellow Pulsating Supergiants: FYPS Point the Way to Missing Red Supergiants
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DOI：
10.3847/1538-4357/ac79b2
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发表时间：
2022-06
期刊：
影响因子：
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通讯作者：
T. Dorn-Wallenstein;E. Levesque;J. Davenport;K. Neugent;B. Morris;K. Bostroem
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作者：
T. Dorn-Wallenstein;E. Levesque;J. Davenport;K. Neugent;B. Morris;K. Bostroem
快黄色脉动超巨星(FYPS)是最近发现的一类演化的大质量脉动体。作为候选的超大天体，以及为数不多的脉动演化的大质量恒星之一，这些天体具有难以置信的潜力，可以改变我们对大质量恒星结构和演化的理解。在这里，我们检查了凌日系外行星调查卫星观测到的麦哲伦星云中126颗冷却超巨星的光曲线，以确定脉动的恒星。在进行质量切割和滤除污染目标后，我们检查了脉动恒星在赫兹-罗素(HR)图上的分布，发现FYPS位于LogL/L⊙≳5.0以上的区域。这一光度边界对应于初始质量为∼18-20M⊙的恒星，这与超新星(SNE)II-P的最大质量红色超巨星前体以及SNE IIb前体的观测性质一致。这一门槛与FYP是后RSG明星的图景一致。最后，我们刻画了FYPS脉动作为它们在HR图中位置的函数的行为。我们发现在较高的有效温度下有低频的脉动，在较低的温度下有较高的频率的脉动，在中温时这两种行为之间有一个转变。FYPS所观察到的性质使其成为未来理论研究的迷人对象。
Fast yellow pulsating supergiants (FYPS) are a recently discovered class of evolved massive pulsators. As candidate supergiant objects, and one of the few classes of pulsating evolved massive stars, these objects have incredible potential to change our understanding of the structure and evolution of massive stars. Here we examine the lightcurves of a sample of 126 cool supergiants in the Magellanic Clouds observed by the Transiting Exoplanet Survey Satellite in order to identify pulsating stars. After making quality cuts and filtering out contaminant objects, we examine the distribution of pulsating stars in the Hertzprung–Russel (HR) diagram, and find that FYPS occupy a region above logL/L⊙≳5.0 . This luminosity boundary corresponds to stars with initial masses of ∼18–20 M ⊙, consistent with the most massive red supergiant progenitors of supernovae (SNe) II-P, as well as the observed properties of SNe IIb progenitors. This threshold is in agreement with the picture that FYPS are post-RSG stars. Finally, we characterize the behavior of FYPS pulsations as a function of their location in the HR diagram. We find low-frequency pulsations at higher effective temperatures, and higher-frequency pulsations at lower temperatures, with a transition between the two behaviors at intermediate temperatures. The observed properties of FYPS make them fascinating objects for future theoretical study.