Gaia-derived luminosities ofKeplerA/F stars and the pulsator fraction across the δ Scuti instability strip
Gaia-derived luminosities ofKeplerA/F stars and the pulsator fraction across the δ Scuti instability strip
复制标题
DOI：
10.1093/mnras/stz590
复制
发表时间：
2019-02
影响因子：
4.8
通讯作者：
S. Murphy;D. Hey;T. V. Reeth;T. Bedding
中科院分区：
文献类型：
--
作者：
S. Murphy;D. Hey;T. V. Reeth;T. Bedding
我们使用Gaia DR2视差来研究星体不稳定带及其周围脉动的恒星的比例，以求出精确的光度。我们将超过15,000颗开普勒A星和F星的样本分为小行星和非小行星，密切关注可能有其他来源的变率。我们发现，18%的星体的主频高于开普勒长节奏奈奎斯特频率(周期1小时)，30%的恒星具有超奈奎斯特变率。我们分析了脉动星分数作为有效温度和光度的函数，发现在{\Delta}SCT不稳定性带中的许多恒星不脉动。脉动率在不稳定带中部达到70%多一点的峰值。结果对用于识别脉动子的幅度阈值不敏感。我们基于观测到的脉动分数定义了一个新的经验不稳定带，它系统地比目前使用的理论条更热。在线目录中提供了恒星温度、亮度和脉动分类。
We study the fraction of stars in and around the {\delta} Scuti instability strip that are pulsating, using {\em Gaia} DR2 parallaxes to derive precise luminosities. We classify a sample of over 15,000 {\em Kepler} A and F stars into {\delta} Sct and non-{\delta} Sct stars, paying close attention to variability that could have other origins. We find that 18 per cent of the {\delta} Sct stars have their dominant frequency above the Kepler long-cadence Nyquist frequency (periods < 1 hr), and 30 per cent have some super-Nyquist variability. We analyse the pulsator fraction as a function of effective temperature and luminosity, finding that many stars in the {\delta} Sct instability strip do not pulsate. The pulsator fraction peaks at just over 70 per cent in the middle of the instability strip. The results are insensitive to the amplitude threshold used to identify the pulsators. We define a new empirical instability strip based on the observed pulsator fraction that is systematically hotter than theoretical strips currently in use. The stellar temperatures, luminosities, and pulsation classifications are provided in an online catalogue.