AI 中文总结
该研究提出行星包层剥离可激发轨道偏心率，用开普勒数据证实跨半径谷行星对间距更大，为半径谷行星是剥离核心的观点提供支持。
AI 中文摘要
我们证明，若行星包层被剥离后，残留气体在系统中停留足够长时间以发生引力相互作用并从行星轨道吸收角动量，就会激发行星轨道偏心率。据估算，少量（百分之几）的包层质量分数即可使单颗行星的偏心率达到约0.1。该过程可能解释半径谷内或附近行星观测到的偏高偏心率。在多行星系统中，剥离的气体可介导相邻行星间的角动量交换，导致行星间距扩大。利用开普勒卫星数据，我们发现，跨半径谷的行星对，其间距系统上确实大于两颗成员均为亚海王星的行星对。这些结果支持以下观点：半径谷内或略低于该区域的行星是丢失质量的行星的剥离核心，因为偏高的偏心率表明气体在系统中停留了足够长时间，得以从行星吸收额外角动量。
英文摘要
We demonstrate that the stripping of planetary envelopes can result in the excitation of planetary orbital eccentricity if the stripped gas remains in the system long enough to interact gravitationally and absorb angular momentum from the planetary orbit. We estimate that envelope mass fractions of a few percent can excite eccentricities of order 0.1 for single planets. This process can potentially explain the elevated eccentricities observed for planets whose radii lie in, or near, the radius valley. In multiple planet systems, the stripped gas can mediate angular momentum exchange between neighbouring planets, causing the separation to expand. Using data from the Kepler satellite, we find that planet pairs, whose members straddle the radius valley, do appear to be systematically wider than those in which both members are sub-Neptunes. These results support the idea that planets in, or just below, the radius valley are the stripped cores of planets that have lost mass, because the elevated eccentricities represent evidence that the gas remained in the system long enough to absorb additional angular momentum from the planet.
Comments9 pages, 5 figures, to be submitted to Open Journal of Astrophysics
