论文标题
为什么温暖的海王星表现出非零偏心率？
Why do warm Neptunes present nonzero eccentricity?
论文作者
论文摘要
大多数海王星质量行星在近距离轨道上（轨道周期少于几天）表现为非零偏心率，通常约为0.15。这是出乎意料的，因为这些行星经历了强烈的潮汐耗散，这应该在时间尺度上比系统年龄短的时间尺度循环。在本文中，我们讨论了一些可能反对身体潮汐的机制，即热气潮，大气的蒸发以及遥远同伴的激发。在前两种情况下，偏心率可以始终如一地增加，而在最后一个情况下，偏心率只能在有限的时间内感到兴奋（但可能超过系统的年龄）。我们展示了这些不同机制的局限性以及其中某些机制的局限性，具体取决于观察到的行星系统的特定特性，解释了其目前观察到的偏心率。
Most Neptune-mass planets in close-in orbits (orbital periods less than a few days) present nonzero eccentricity, typically around 0.15. This is somehow unexpected, as these planets undergo strong tidal dissipation that should circularize their orbits in a time-scale shorter than the age of the system. In this paper we discuss some mechanisms that can oppose to bodily tides, namely, thermal atmospheric tides, evaporation of the atmosphere, and excitation from a distant companion. In the first two cases, the eccentricity can increase consistently, while in the last one, the eccentricity can only be excited for a limited amount of time (that may nevertheless exceed the age of the system). We show the limitations of these different mechanisms and how some of them could, depending on specific properties of the observed planetary systems, account for their presently observed eccentricities.
