亚海王星的自转与内部演化耦合
Coupled Orbital and Interior Evolution of Sub-Neptunes
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中文总结 AI 辅助
本文通过耦合冷却、大气损失与潮汐迁移的演化模型，检验亚海王星发生率随年龄的变化，发现高偏心率迁移可解释早期上升，但无法解释后期下降，需补充新物理或形成机制。
中文摘要 AI 辅助
最近的观测首次给出了年轻系外行星的统计特征。近距离亚海王星的发生率似乎从年轻（10-100 Myr）到中等年龄（100 Myr 至 1 Gyr）阶段上升，然后在较老（≳ 1 Gyr）的开普勒巡天星族中急剧下降。本文检验这些观测能否由行星冷却、大气质量损失和潮汐轨道迁移的效应所解释，我们通过一个完全耦合的演化框架对这些效应进行建模。轨道演化被假定仅通过高偏心率迁移（HEM）进行，以估计该迁移通道可能的最大贡献。实际上，预计只有一部分行星系统会经历高偏心率迁移。我们发现高偏心率迁移迅速填充近距离亚海王星区域，在最初约 15 Myr 内产生发生率的急剧上升。在此早期阶段之后，发生率仅微弱演化。虽然模拟的从年轻到中等年龄的演化趋势在不确定性范围内与观测大体一致，但它不支持由潮汐迁移驱动的持续年轻到中等年龄上升的观点。它也无法重现从中等年龄到老年阶段观测到的发生率急剧下降，这促使未来模型需加入额外的物理机制或形成通道。
英文摘要
Recent observations have yielded the first measurements of young exoplanet demographics. Close-in sub-Neptune occurrence rates appear to rise from young ($10-100$ Myr) to intermediate (100 Myr $-$ 1 Gyr) ages and then decline sharply in the old ($\gtrsim 1$ Gyr) Kepler field population. In this paper, we test whether these observations can be explained by the effects of planetary cooling, atmospheric mass loss, and tidal orbital migration, which we model through a fully coupled evolution framework. The orbital evolution is assumed to operate exclusively through high-eccentricity migration, in effort to estimate the maximum possible contribution from this migration channel. In reality, only a subset of planetary systems are expected to undergo HEM. We find that high-eccentricity migration rapidly populates the close-in sub-Neptune bin, producing a sharp rise in occurrence within the first $\sim 15$ Myr. After this early phase, the occurrence evolves only weakly. While the modeled young to intermediate-age evolution is broadly consistent with the observed trend within the uncertainty limits, it does not support the idea of a sustained young-to-intermediate rise driven by tidal migration. It also fails to reproduce the sharp decline in occurrence seen from intermediate to old ages, motivating additional physics or formation channels to be included in future models.
发表机构
- Massachusetts Institute of Technology（麻省理工学院）
- MIT Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology（麻省理工学院卡弗里天体物理学与空间研究所）
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