论文标题
Tess-Keck调查II：超短期时期的岩石行星及其兄弟姐妹经过银河厚盘星TOI-561
The TESS-Keck Survey II: An Ultra-Short Period Rocky Planet and its Siblings Transiting the Galactic Thick-Disk Star TOI-561
论文作者
论文摘要
我们报告了TOI-561的发现，TOI-561是一个包含岩石，超短暂时期星球（USP）的银河厚磁盘中的多行星系统。这款明亮的（$ v = 10.2 $）恒星托管了NASA TESS任务中标识的三个小型过渡行星：TOI-561 B（TOI-561.02，p = 0.44天，$ r_b = 1.45 \ pm0.11 \，r_ \ oplus $），r_ \ oplus $） $ r_c = 2.90 \ pm0.13 \，r_ \ oplus $）和d（toi-561.03，p = 16.3天，$ r_d = 2.32 \ pm0.16 \，r_ \ oplus $）。恒星是化学上的（[fe/h] $ = -0.41 \ pm0.05 $，[$α$/h] $ =+0.23 \ pm0.05 $），并且在运动上与银河系厚的磁盘总体一致，使TOI-561成为最旧的（$ 10 \ pm3 \，$ gy，$ gyr）及其最大的planety and PlaneD and PlaneD and discufdency and tocducty。我们通过W. M. Keck天文台高分辨率梯形光谱仪的径向速度动态确认行星B和C。 Planet B的质量和密度为$ 3.2 \ pm0.8 \，m_ \ oplus $和$ 5.5^{+2.0} _ { - 1.6} \，$ g $ \，$ g $ \，$ cm $^{ - 3} $，一致，与摇滚的成分一致。它的低于平均水平的密度与铁贫穷的组成一致，尽管不排除类似地球的铁与丝状比率。 Planet C为$ 7.0 \ pm2.3 \，m_ \ oplus $和$ 1.6 \ pm0.6 \，$ g $ \，$ cm $^{ - 3} $，与内部岩石核心叠加一致，带有低质量伏击信封。 Planet D的光度法的几个属性（我们没有动态检测）使分析变得复杂，但是我们会以高对比度成像，基于地面的光度随访和径向速度进行审查。 TOI-561 B是围绕银河厚盘恒星的第一个岩石世界，该星星的径向速度和热排放研究最好的岩石行星之一证实。
We report the discovery of TOI-561, a multi-planet system in the galactic thick disk that contains a rocky, ultra-short period planet (USP). This bright ($V=10.2$) star hosts three small transiting planets identified in photometry from the NASA TESS mission: TOI-561 b (TOI-561.02, P=0.44 days, $R_b = 1.45\pm0.11\,R_\oplus$), c (TOI-561.01, P=10.8 days, $R_c=2.90\pm0.13\,R_\oplus$), and d (TOI-561.03, P=16.3 days, $R_d=2.32\pm0.16\,R_\oplus$). The star is chemically ([Fe/H]$=-0.41\pm0.05$, [$α$/H]$=+0.23\pm0.05$) and kinematically consistent with the galactic thick disk population, making TOI-561 one of the oldest ($10\pm3\,$Gyr) and most metal-poor planetary systems discovered yet. We dynamically confirm planets b and c with radial velocities from the W. M. Keck Observatory High Resolution Echelle Spectrometer. Planet b has a mass and density of $3.2\pm0.8\,M_\oplus$ and $5.5^{+2.0}_{-1.6}\,$g$\,$cm$^{-3}$, consistent with a rocky composition. Its lower-than-average density is consistent with an iron-poor composition, although an Earth-like iron-to-silicates ratio is not ruled out. Planet c is $7.0\pm2.3\,M_\oplus$ and $1.6\pm0.6\,$g$\,$cm$^{-3}$, consistent with an interior rocky core overlaid with a low-mass volatile envelope. Several attributes of the photometry for planet d (which we did not detect dynamically) complicate the analysis, but we vet the planet with high-contrast imaging, ground-based photometric follow-up and radial velocities. TOI-561 b is the first rocky world around a galactic thick-disk star confirmed with radial velocities and one of the best rocky planets for thermal emission studies.
