Inferring the rotation period distribution of stars from their projected rotation velocities and radii: Application to late-F/early-G Kepler stars
Inferring the rotation period distribution of stars from their projected rotation velocities and radii: Application to late-F/early-G Kepler stars
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从恒星的预计旋转速度和半径推断其旋转周期分布：应用于晚 F/早 G 开普勒星
DOI：
10.1093/mnras/stab3650
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发表时间：
2022
影响因子：
4.8
通讯作者：
Oliver J. Hall
中科院分区：
文献类型：
--
作者：
Kento Masuda; Erik A. Petigura; Oliver J. Hall
虽然恒星自转周期Prot可以通过宽带光度法测量，但对于较慢的自转周期，光度调制变得更难检测到，这可能会对Prot分布的长周期尾部的测量产生偏差。或者，可以从恒星的投影自转速度vSINI和RADIIR来推断恒星的分布，而不会对光度学上安静的恒星产生偏见。我们使用分层贝叶斯框架解决了这一推断问题，该框架(I)适用于具有非高斯不确定性的vsini和r2的异方差测量，并且(Ii)不需要真实Prot分布的简单参数形式。我们在模拟数据集上对该方法进行了测试，结果表明，除非真实分布包含尖锐的不连续，否则可以从≳100组vSINI和R分别以4%和4%的精度恢复真实的Prot分布。我们将这种方法应用于开普勒场中由Keck/Hires光谱测量的144颗晚F/早G矮星的样本，发现这些恒星的典型自转周期与从Keplerlight曲线测量的光度学周期相似：我们没有发现光度学样本中遗漏的大量慢旋转者，尽管我们发现了光度学样本对年轻、快速旋转的恒星有偏见的证据。我们的结果也与具有相似年龄和有效温度的Protfor Keplerstar的恒星地震测量结果一致，并表明超出主序寿命中间的恒星自转速度比标准磁制动定律预测的要快。
While stellar rotation periodsProtmay be measured from broad-band photometry, the photometric modulation becomes harder to detect for slower rotators, which could bias measurements of the long-period tail of theProtdistribution. Alternatively, theProtdistribution of stars can be inferred from their projected rotation velocitiesvsiniand radiiR, without being biased against photometrically quiet stars. We solve this inference problem using a hierarchical Bayesian framework, which (i) is applicable to heteroscedastic measurements ofvsiniandRwith non-Gaussian uncertainties and (ii) does not require a simple parametric form for the trueProtdistribution. We test the method on simulated data sets and show that the trueProtdistribution can be recovered from ≳ 100 sets ofvsiniandRmeasured with precisions ofand 4 per cent, respectively, unless the true distribution includes sharp discontinuities. We apply the method to a sample of 144 late-F/early-G dwarfs in theKeplerfield withvsinimeasured from Keck/HIRES spectra, and find that the typical rotation periods of these stars are similar to the photometric periods measured fromKeplerlight curves: we do not find a large population of slow rotators that are missed in the photometric sample, although we find evidence that the photometric sample is biased for young, rapidly rotating stars. Our results also agree with asteroseismic measurements ofProtforKeplerstars with similar ages and effective temperatures, and show thatstars beyond the middle of their main-sequence lifetimes rotate faster than predicted by standard magnetic braking laws.