论文标题
基于开普勒和$ GAIA $数据的系外行星候选人的空间分布
Spatial distribution of exoplanet candidates based on Kepler and $Gaia$ data
论文作者
论文摘要
银河系中系外行星的空间分布对于我们对行星形成和进化的理解很重要。我们旨在确定太阳邻居和开放簇附近发生系外行星的空间梯度。为此，我们将开普勒和Gaia DR2数据组合在一起，将开普勒任务采样的音量分解为某些空间箱。我们确定了每个垃圾箱的未校正和偏置校正的系外行星频率和金属性。未校正的系外行星频率有明显的下降，F型星的距离，沿银河经度L = 90摄氏度的距离增加，并且高度高于银河平面。我们发现，金属性行为并不是距离增加距离恒星周围系外行星频率下降的原因。我们认为，未经校正的系外行星频率的上述梯度是由于较小的恒星周围未检测到的较小行星的单个偏差而产生的。当我们纠正观察性偏见时，大多数这些系外行星频率中的大多数在统计上都变得微不足道。在3 sigma水平下，只有距离距离的距离略有下降，而距离距离距离保持显着。除此之外，开普勒视野中系外行星的空间分布与均匀的空间分布兼容。同时，我们没有发现与开放群集距离增加的系外行星频率发生重大变化。作为副产品，我们确定了六个开放群集成员的系外行星主持人候选人。其中有四个在NGC 6811（KIC 9655005，KIC 9533489，Kepler-66，Kepler-67）中，而两个属于NGC 6866（KIC 8396288，KIC 83331612）。六个中有两个已经众所周知是集群成员。
The spatial distribution of exoplanets in the Galaxy is important for our understanding of planet formation and evolution. We aim to determine the spatial gradients of exoplanet occurrence in the Solar neighbourhood and in the vicinity of open clusters. We combined Kepler and Gaia DR2 data for this purpose, splitting the volume sampled by the Kepler mission into certain spatial bins. We determined an uncorrected and bias-corrected exoplanet frequency and metallicity for each bin. There is a clear drop in the uncorrected exoplanet frequency with distance for F-type stars, a decline with increasing distance along the Galactic longitude l=90 deg, and a drop with height above the Galactic plane. We find that the metallicity behaviour cannot be the reason for the drop of the exoplanet frequency around F stars with increasing distance. We argue that the above-mentioned gradients of uncorrected exoplanet frequency result from a single bias of undetected smaller planets around fainter stars. When we correct for observational biases, most of these gradients in exoplanet frequency become statistically insignificant. Only a slight decline of the planet occurrence with distance for F stars remains significant at the 3 sigma level. Apart from that, the spatial distribution of exoplanets in the Kepler field of view is compatible with a homogeneous one. At the same time, we do not find a significant change in the exoplanet frequency with increasing distance from open clusters. As a byproduct, we identified six exoplanet host star candidates that are members of open clusters. Four of them are in the NGC 6811 (KIC 9655005, KIC 9533489, Kepler-66, Kepler-67) and two belong to NGC 6866 (KIC 8396288, KIC 8331612). Two out of the six had already been known to be cluster members.
