论文标题
加利福尼亚与侦探的调查。 X.半径间隙随着恒星质量，金属性和年龄的函数的作用
The California-Kepler Survey. X. The Radius Gap as a Function of Stellar Mass, Metallicity, and Age
论文作者
论文摘要
2017年，加利福尼亚州的调查（CKS）发布了其第一个数据发布（DR1），该数据发布（DR1）是1305 Planet Hosts的高分辨率光谱。 Refined CKS planet radii revealed that small planets are bifurcated into two distinct populations: super-Earths (smaller than 1.5 $R_E$) and sub-Neptunes (between 2.0 and 4.0 $R_E$), with few planets in between (the "Radius Gap.") Several theoretical models of the Radius Gap predict variation with stellar mass, but testing these predictions are challenging with CKS DR1 due to its limited $ m_ \ star $范围为0.8-1.4 $ m_ \ odot $。在这里，我们将CKS DR2提供411个额外的光谱和派生属性，重点是0.5-0.8 $ m_ \ odot $的星星。我们发现半径差距遵循$ r_p \ propto p^m $，其中$ m = -0.10 \ pm 0.03 $，与XUV和核心驱动的质量损失机制的预测一致。我们没有发现$ m $随$ m_ \ star $而变化的证据。我们观察到平均亚纽扣大小与$ m_ \ star $之间的相关性。超过0.5至1.4 $ m_ \ odot $，平均子纳普从2.1增至2.6 $ r_e $，遵循$ r_p \ propto m_ \ star^α$，$α= 0.25 \ pm 0.03 $。相比之下，没有可检测到的超级诞生。这些$ m_ \ star $ - $ r_p $趋势表明，原始磁盘可以有效地产生核心质量$ m_c $的阈值质量，根据$ m_c \ $ m_c \ \ 10 m_e〜（m_ \ star / m_ \ odot）$。亚纽马大小与恒星金属性之间没有显着的相关性（超过$ - $ 0.5至$+$ 0.5 dex），这表明行星信封不透明度与恒星金属之间存在弱关系。最后，随着恒星年龄（超过1至10 Gyr）的次纳及数量没有显着差异，这表明大多数信封收缩在$ \ sim $ 1 $ 1 GYR之后结束。
In 2017, the California-Kepler Survey (CKS) published its first data release (DR1) of high-resolution optical spectra of 1305 planet hosts. Refined CKS planet radii revealed that small planets are bifurcated into two distinct populations: super-Earths (smaller than 1.5 $R_E$) and sub-Neptunes (between 2.0 and 4.0 $R_E$), with few planets in between (the "Radius Gap.") Several theoretical models of the Radius Gap predict variation with stellar mass, but testing these predictions are challenging with CKS DR1 due to its limited $M_\star$ range of 0.8-1.4 $M_\odot$. Here, we present CKS DR2 with 411 additional spectra and derived properties focusing on stars of 0.5-0.8 $M_\odot$. We found the Radius Gap follows $R_p \propto P^m$ with $m = -0.10 \pm 0.03$, consistent with predictions of XUV- and core-powered mass-loss mechanisms. We found no evidence that $m$ varies with $M_\star$. We observed a correlation between the average sub-Neptune size and $M_\star$. Over 0.5 to 1.4 $M_\odot$, the average sub-Neptune grows from 2.1 to 2.6 $R_E$, following $R_p \propto M_\star^α$ with $α= 0.25 \pm 0.03$. In contrast, there is no detectable change for super-Earths. These $M_\star$-$R_p$ trends suggests that protoplanetary disks can efficiently produce cores up to a threshold mass of $M_c$, which grows linearly with stellar mass according to $M_c \approx 10 M_E~(M_\star / M_\odot)$. There is no significant correlation between sub-Neptune size and stellar metallicity (over $-$0.5 to $+$0.5 dex) suggesting a weak relationship between planet envelope opacity and stellar metallicity. Finally, there is no significant variation in sub-Neptune size with stellar age (over 1 to 10 Gyr), which suggests that the majority of envelope contraction concludes after $\sim$1 Gyr.
