8个DAV型白矮星的星震学研究中来自视差和平均周期间距的约束
Constraints from parallaxes and average period spacings in the asteroseismic study of 8 DAVs
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中文总结 AI 辅助
本研究选取8个DAV型白矮星，利用其脉动光谱推导渐近周期间距，结合Gaia视差数据等约束氢层厚度，证实氢层较厚的白矮星更常见，且Gaia给出的有效温度低于光谱学结果。
中文摘要 AI 辅助
借助Kepler、TESS、Gaia等空间任务，我们拥有大量可用于白矮星星震学的脉动白矮星数据。我们研究了氢层较薄与较厚的白矮星占比问题，还给出了碳氧核、氢大气白矮星的质量-半径关系，该关系可结合星等和距离测量来约束白矮星的质量与有效温度。我们选取8个拥有丰富脉动光谱的氢大气脉动白矮星（DAV），从其脉动光谱可推导出渐近周期间距，进而无需逐周期拟合就能确定模型的氢、氦包层厚度。我们发现多数白矮星氢层更厚，确定了氦层底部位置的上限为Mr = 10^-2.2，这与恒星演化模型一致。我们证实了早期研究利用质量-半径关系和Gaia数据确定白矮星有效温度的结论，即Gaia数据给出的白矮星有效温度系统性低于光谱学结果，我们的结果还支持氢层较厚的白矮星比氢层较薄的更常见这一假设。
英文摘要
With space missions such as Kepler, TESS, and Gaia, we have a wealth of data on pulsating white dwarfs that can be leveraged in white dwarf asteroseismology. We address the question of the proportion of white dwarfs with thin hydrogen layers versus those with thick hydrogen layers. We also provide a mass-radius relation for carbon-oxygen core, hydrogen atmosphere white dwarfs. Such a relationship can be used in conjunction with magnitudes and distance measurements to constrain the mass and effective temperature of the white dwarfs. We select eight hydrogen atmosphere, pulsating white dwarfs (DAVs), for their rich pulsation spectra. From such pulsation spectra, we can derive an asymptotic period spacing, which in turn allows us to determine the thickness of the hydrogen and helium envelope of the models, without having to perform period by period fitting. We find that the majority of the white dwarfs have thicker hydrogen layers and determine an upper limit of Mr = 1 - 10 to the -2.2 for the location of the base of the helium layer, in accordance with stellar evolution models. We confirm a finding from earlier studies that used a mass-radius relation and Gaia data to determine the effective temperatures of white dwarfs. The Gaia data systematically points to white dwarfs of lower effective temperature than indicated by the spectroscopy. Our results also support the hypothesis that white dwarfs with thicker hydrogen layers are more common than those with thinner layers.
