论文标题
缩放K2。 I. 222,088 k2星的修订参数和1.9 $ r _ {\ oplus} $的K2 Planet Radius Valley
Scaling K2. I. Revised Parameters for 222,088 K2 Stars and a K2 Planet Radius Valley at 1.9 $R_{\oplus}$
论文作者
论文摘要
黄道平面输入目录中K2星的恒星特性的先前测量（Epic; Huber等人，2016年）在很大程度上依赖于光度法和适当的运动测量，并提供了一些可用光谱和视差的附加信息。将GAIA DR2距离与来自大型天空区域多对象纤维光谱望远镜（Lamost）DR5的有效温度，表面重力和金属度的光谱测量结合在一起，我们计算了26,838 k2星的更新更新的恒星半径和质量。对于没有lamost频谱的195,250个目标，我们使用在Lamost样品上训练的光度颜色上的随机森林回归得出了恒星参数。总体而言，我们测量了222,088 A，F，G，K和M型K2星的光谱类型，有效温度，表面重力，金属性，半径和质量。借助这些新的恒星半径，我们对299次确认的299和517候选K2行星半径进行了简单的重新分析，从1--13中阐明了一个独特的星球半径谷，左右是1.9 $ r _ {\ oplus} $，因此与Kepler PlaneTess and Keplerplanes and TentEctery and tentepery and tentery senlent and tentectionally seject and the the templanse and teentery neck 2 $ r _ {\ oplus} $。这些更新的恒星参数是计算K2行星出现率的过程中的关键步骤。
Previous measurements of stellar properties for K2 stars in the Ecliptic Plane Input Catalog (EPIC; Huber et al. 2016) largely relied on photometry and proper motion measurements, with some added information from available spectra and parallaxes. Combining Gaia DR2 distances with spectroscopic measurements of effective temperatures, surface gravities, and metallicities from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) DR5, we computed updated stellar radii and masses for 26,838 K2 stars. For 195,250 targets without a LAMOST spectrum, we derived stellar parameters using random forest regression on photometric colors trained on the LAMOST sample. In total, we measured spectral types, effective temperatures, surface gravities, metallicities, radii, and masses for 222,088 A, F, G, K, and M-type K2 stars. With these new stellar radii, we performed a simple reanalysis of 299 confirmed and 517 candidate K2 planet radii from Campaigns 1--13, elucidating a distinct planet radius valley around 1.9 $R_{\oplus}$, a feature thus far only conclusively identified with Kepler planets, and tentatively identified with K2 planets. These updated stellar parameters are a crucial step in the process toward computing K2 planet occurrence rates.
