论文标题
Kepler-90：巨型过境时期变化显示了超级阵利
Kepler-90: Giant transit-timing variations reveal a super-puff
论文作者
论文摘要
由行星之间的重力引起的分类时正时变化（TTV）可用于确定行星质量和轨道参数。大多数观察到的TTV在时间上很小且正弦，导致质量和轨道参数之间的变性。在这里，我们报告了Kepler-90G和Kepler-90H的TTV分析，该分析显示长达25小时的TTV。通过优化，我们找到了一个独特的解决方案，该解决方案使我们能够约束所有轨道参数。 Kepler-90g和90h的最佳拟合度为$ 15.0^{+0.9} _ { - 0.8} $ $ $ M _ {\ bigoplus} $（arter Mass）和$ 203^{+5} _ { - 5} _ { - 5} m _ { $ 0.15 \ pm 0.05 \，{\ rm g \，cm^{ - 3}} $。轨道参数解决方案的独特性可以实现长期的动态整合，这表明尽管它们的周期接近2：3轨道共振，但它们并未锁定在共振中，并且在数十亿年内配置稳定。系统的动态历史表明，行星相互作用能够提高偏心率并在初始形成后打破谐振锁。
Exoplanet Transit Timing Variations (TTVs) caused by gravitational forces between planets can be used to determine planetary masses and orbital parameters. Most of the observed TTVs are small and sinusoidal in time, leading to degeneracies between the masses and orbital parameters. Here we report a TTV analysis of Kepler-90g and Kepler-90h, which exhibit large TTVs up to 25 hours. With optimization, we find a unique solution which allows us to constrain all of the orbital parameters. The best fit masses for Kepler-90g and 90h are $15.0^{+0.9}_{-0.8}$ $M_{\bigoplus}$ (Earth mass) and $203^{+5}_{-5}M_{\bigoplus}$, respectively, with Kepler-90g having an unusually low apparent density of $0.15\pm 0.05\, {\rm g\,cm^{-3}}$. The uniqueness of orbital parameter solution enables a long-term dynamical integration, which reveals that although their periods are close to 2:3 orbital resonance, they are not locked in resonance, and the configuration is stable over billions of years. The dynamical history of the system suggests that planet interactions are able to raise the eccentricities and break the resonant lock after the initial formation.
