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arXiv 1809.07451astro-ph.SR
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蓝色大振幅脉动(BLAPs):可能的起源,进化状态和它们脉动的性质

Blue Large-Amplitude Pulsators (BLAPs): possible origin, evolutionary status, and nature of their pulsations

Alejandro H. Córsico, Alejandra D. Romero, Leandro G. Althaus, Ingrid Pelisoli, S. O. Kepler

摘要:

蓝色大振幅脉冲星(blue Large-Amplitude Pulsators,BLAPs)是一类新的脉冲星。它们是有效温度为$T_{\rm eff}\sim 30\,000$ K和表面重力为$\log g \sim 4.9$的热星,其脉动周期在$\sim 20-40$ min范围内。在Romero等人(2018)中,我们提出BLAP是热的低质量He核前白矮星(WD)星,其脉动为高阶非径向$g$(重力)模式或低阶径向模式,包括基本径向模式。由于与$\log T \sim 5.25$不透明度中的$Z$凸起相关的$κ$机制,在观测范围内具有周期的理论模式是不稳定的。在这项工作中,我们扩展了Romero等人的研究。(2018)通过评估非径向$g$模式和径向模式的周期变化率,并将其与BLAP的测量值进行比较,试图验证所提出的进化方案,并辨别观察到的模式是高阶$g$模式还是径向模式。

英文摘要:

The Blue Large-Amplitude Pulsators (BLAPs) constitute a new class of pulsating stars. They are hot stars with effective temperatures of $T_{\rm eff}\sim 30\,000$ K and surface gravities of $\log g \sim 4.9$, that pulsate with periods in the range $\sim 20-40$ min. In Romero et al. (2018), we proposed that BLAPs are hot low-mass He-core pre-white dwarf (WD) stars that pulsate either in high-order non-radial $g$(gravity) modes or low-order radial modes, including the fundamental radial mode. The theoretical modes with periods in the observed range are unstable due to the $κ$ mechanism associated with the $Z$ bump in the opacity at $\log T \sim 5.25$. In this work, we extend the study of Romero et al. (2018) by assessing the rate of period changes of nonradial $g$ modes and radial modes and comparing them with the values measured for BLAPs, in an attempt to validate the proposed evolutionary scenario, and to discern whether the observed modes are high-order $g$ modes or radial modes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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