AI 中文总结
本文综述行星抛射的四种机制及相关预测，指出当前及未来微引力透镜观测可检验现有模型、区分抛射机制，以揭示恒星环境中系外行星的种群级结构。
AI 中文摘要
微引力透镜和直接成像观测推断出的自由漂浮行星普遍存在，表明行星抛射——即原本环绕恒星宿主形成的行星变得引力上不受束缚的过程——是普遍存在的。目前已提出四种引发行星抛射的总体机制：邻近行星的近距离接近、双星或多恒星系统的不稳定性、恒星与行星的飞掠，以及主序后恒星演化。本文综述了行星抛射的潜在机制，以及每种机制衍生的预测。当前及即将开展的微引力透镜观测有望检验现有模型，区分潜在的行星抛射机制，进一步揭示恒星环境中系外行星的种群级结构。
英文摘要
The ubiquity of free-floating planets inferred from microlensing and direct imaging surveys suggests that planetary ejection---a process in which planets initially born encircling a stellar host become gravitationally unbound---is common. Four overarching mechanisms have been proposed to induce planetary ejection: close approaches of neighboring planets, instabilities in binary or multi-star systems, stellar and planetary flybys, and post-main-sequence stellar evolution. Here we review the mechanisms underlying planetary ejection, as well as predictions derived from each. Current and upcoming microlensing surveys offer the potential to test existing models and distinguish between planetary ejection mechanisms, offering further insight into the demographic-level architectures of exoplanets across stellar environments.
Commentsinvited review; accepted to PASP. Final published version
