研究主恒星MS后演化对近距离行星轨道的影响。II。一颗巨大的行星在RGB恒星HIP63242附近的轨道上

行星吸积在创造下一代红巨星快速旋转器中的作用

The Role of Planet Accretion in Creating the Next Generation of Red Giant Rapid Rotators

野外红巨星的快速旋转是一种相对罕见但研究充分的现象;在这里，我们研究了行星吸积在这些恒星旋转中的潜在作用。利用Zahn的潮汐摩擦理论和恒星演化模型，我们计算了一颗行星的轨道衰减到其不断演变的宿主恒星和由此产生的角动量转移到恒星对流包络。该实验评估了99个已知系外行星宿主恒星样本的红巨星分支（RGB）上行星摄入和快速旋转的频率。我们发现，已知的系外行星确实能够产生快速的旋转体;然而，由于行星摄入的预期比例仅为当今红巨星调查中看到的总量的10%。在被吸收的行星中，我们发现那些初始半长轴较小的行星更有可能产生快速旋转的行星，因为这些行星在恒星的转动惯量最小时被吸积。我们还发现，许多行星可能会被摄入之前的RGB阶段，相反的预期，吸积通常会发生时，恒星半径显着扩大的巨人。最后，我们的模型表明，来自被摄入行星的快速旋转信号最有可能在较低的RGB上看到，这也是自旋上升的替代机制，例如，角动量从恒星核心释放出来，不起作用。因此，在较低的RGB上的快速旋转是寻找经历过行星吸积的系统的明确证据的最佳候选者。

化学丰度塑造历史（CASH）。I. 巨型行星轨道周期与宿主恒星C/O比值之间的联系

Chemical Abundances Shape History (CASH). I. A Link between Giant Planets Orbital Periods and Host Stellar C/O Ratios

研究揭示恒星C/O比值与巨行星轨道周期的关系，指出高C/O比值促进外盘区域固态物质积累，从而影响巨行星形成与迁移。

Do Metal-Rich Stars Make Metal-Rich Planets? New Insights on Giant Planet Formation from Host Star Abundances

The relationship between the compositions of giant planets and their host stars is of fundamental interest in understanding planet formation. The solar system giant planets are enhanced above solar composition in metals, both in their visible atmospheres and bulk compositions. A key question is whether the metal enrichment of giant exoplanets is correlated with that of their host stars. Thorngren et al. (2016) showed that in cool (Teq < 1000 K) giant exoplanets, the total heavy-element mass increases with total Mp and the heavy element enrichment relative to the parent star decreases with tota…

The California Legacy Survey III. On The Shoulders of (Some) Giants: The Relationship between Inner Small Planets and Outer Massive Planets

We use a high-precision radial velocity survey of FGKM stars to study the conditional occurrence of two classes of planets: close-in small planets (0.023--1 au, 2--30 Earth masses) and distant giant planets (0.23--10 au, 30--6000 Earth masses). We find that $41^{+15}_{-13}\%$ of systems with a close-in, small planet also host an outer giant, compared to $17.6^{+2.4}_{-1.9}\%$ for stars irrespective of small planet presence. This implies that small planet hosts may be enhanced in outer giant occurrence compared to all stars with $1.7σ$ significance. Conversely, we estimate that $42^{+17}_{-13}\…

High resolution Spectra of Earth-Like Planets Orbiting Red Giant Host Stars

In the near future we will have ground- and space-based telescopes that are designed to observe and characterize Earth-like planets. While attention is focused on exoplanets orbiting main sequence stars, more than 150 exoplanets have already been detected orbiting red giants, opening the intriguing question of what rocky worlds orbiting in the habitable zone of red giants would be like and how to characterize them. We model reflection and emission spectra of Earth-like planets orbiting in the habitable zone of red giant hosts with surface temperatures between 5200 and 3900 K at the Earth-equiv…

在拥有红巨星的行星中是否存在金属丰度增强？

Is there a metallicity enhancement in planet hosting red giants?

宾夕法尼亚州立大学/托鲁托大学演化恒星周围行星天文学搜索中心是一个高精度的径向速度（RV）调查，旨在探测巨星周围的行星。它是基于9.2米霍比-埃伯利望远镜获得的观测结果。由于红巨星高精度RV数据的正确解释需要对目标进行完整的光谱分析，因此我们对调查中包含的所有恒星进行光谱建模。通常情况下，除了恒星的光度和温度之外，自转速度和金属丰度也被确定，这使我们能够估计恒星的年龄和质量。在这里，我们提出了在我们的样品中的金属丰度研究的初步结果。我们搜索一个金属丰度的依赖性类似的矮星通过比较我们的结果为样本的22个巨人早于K5显示显着的RV变化与对照样本的58个相对RV稳定的恒星。