标题： 开普勒探测的类太阳恒星周围0.25天文单位内的行星出现率 显示英文标题

标题： Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler

摘要： 我们报告了围绕GK型恒星的轨道周期(P)小于50天的行星的分布情况，按行星半径(R_p)、轨道周期(P)和恒星有效温度(Teff)进行分类。 这些结果基于开普勒任务发现的1,235颗行星（正式称为“行星候选体”），其中包括半径小至2个地球半径(Re)的几乎完整的检测行星集合。 对于每个156,000颗目标恒星，我们评估了行星在R_p和P函数下的可检测性。 我们还校正了凌日几何概率，R*/a。 我们首先考虑“太阳子集”中的恒星，其Teff为4100-6100 K，logg为4.0-4.9，开普勒视星等Kp < 15星等。 我们仅包括噪声足够低以允许检测到2 Re以下行星的恒星。 我们在R_p和P的小区域内统计行星，并除以所包含的目标恒星数以计算每个区域的行星出现率。 行星的出现率变化超过三个数量级，并且在我们研究中随着行星半径减小到最小值（2 Re）和轨道周期延长到最长值（50天，约0.25 AU）显著增加。 对于P < 50天的情况，半径分布由幂律给出，df/dlogR= k R^\alpha 。 随着行星尺寸减小，行星出现率迅速增加，这与核心吸积理论一致，但与种群合成模型不一致。 我们将出现率作为P的函数拟合到一个具有指数截断的幂律模型，在临界周期P_0以下。 对于较小的行星，P_0具有较大的值，这表明迁移行星的“停车距离”随着行星尺寸减小而向外移动。 我们还测量了Teff = 3600-7100 K范围内的行星出现率，涵盖了M0到F2矮星。 开普勒场中2-4 Re行星的出现率随Teff降低而增加，使得这些小行星在较冷的恒星周围比我们样本中最热的恒星多七倍。 [缩略] 显示英文摘要

摘要： We report the distribution of planets as a function of planet radius (R_p), orbital period (P), and stellar effective temperature (Teff) for P < 50 day orbits around GK stars. These results are based on the 1,235 planets (formally "planet candidates") from the Kepler mission that include a nearly complete set of detected planets as small as 2 Earth radii (Re). For each of the 156,000 target stars we assess the detectability of planets as a function of R_p and P. We also correct for the geometric probability of transit, R*/a. We consider first stars within the "solar subset" having Teff = 4100-6100 K, logg = 4.0-4.9, and Kepler magnitude Kp < 15 mag. We include only those stars having noise low enough to permit detection of planets down to 2 Re. We count planets in small domains of R_p and P and divide by the included target stars to calculate planet occurrence in each domain. Occurrence of planets varies by more than three orders of magnitude and increases substantially down to the smallest radius (2 Re) and out to the longest orbital period (50 days, ~0.25 AU) in our study. For P < 50 days, the radius distribution is given by a power law, df/dlogR= k R^\alpha. This rapid increase in planet occurrence with decreasing planet size agrees with core-accretion, but disagrees with population synthesis models. We fit occurrence as a function of P to a power law model with an exponential cutoff below a critical period P_0. For smaller planets, P_0 has larger values, suggesting that the "parking distance" for migrating planets moves outward with decreasing planet size. We also measured planet occurrence over Teff = 3600-7100 K, spanning M0 to F2 dwarfs. The occurrence of 2-4 Re planets in the Kepler field increases with decreasing Teff, making these small planets seven times more abundant around cool stars than the hottest stars in our sample. [abridged]