发表机构
Vanderbilt University（范德堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
探讨白矮星形成反冲对自由漂浮行星的影响，研究发现它虽直接使约1%行星脱离，但在约40%长周期多行星系统中引发动力学不稳定，可能使约一半系统产生行星喷射和自由漂浮行星，还会使其加热，形成可观测的子种群。
AI 中文摘要
自由漂浮行星（FFPs）是一类不环绕恒星的系外行星，十分常见。其形成机制多样，本文探索白矮星（WD）形成反冲这种适用于旧行星系统的形成情景。研究表明，WD形成反冲虽直接使约1%已知行星和系外行星脱离，但在约40%已知长周期多行星系统中引发动力学不稳定，约一半此类系统可能导致行星喷射和FFP产生。通过WD反冲产生的FFP还会因宿主恒星增强的AGB光度经历显著且持久的加热。鉴于WD反冲速度低，此类变暖的FFP在形成后几百万年仍可与原宿主恒星关联。因此，WD形成反冲贡献了一个独特的、可观测识别的FFP子种群，占银河系FFP的百分之几，与即将进行的罗曼银河系系外行星调查结果相关。
英文摘要
Free-Floating Planets (FFPs) are a distinct class of exoplanets that do not orbit stars but are nevertheless found to be very common. A variety of formation mechanisms have been proposed as their origin, such as "star-like" direct collapse from gas and dust clouds or ejection from young planetary systems via dynamical instabilities. Here, another possible formation scenario is explored that would instead apply for old planetary systems, in the form of White Dwarf (WD) formation kicks. Observations over recent years have shown that WDs experience a mild recoil kick during their formation from Asymptotic Giant Branch (AGB) stars. Here we show that, while WD formation kicks directly unbind only $\sim1\%$ of the known planet and exoplanet population, they drive dynamical instabilities in $\gtrsim40\%$ of known long-period multi-planet systems, likely leading to planet ejection and FFP generation by most WDs. We also show that FFPs generated via WD kicks will have undergone potentially significant and long-lasting heating via their host stars' enhanced AGB luminosities. Given the low ejection velocities due to the weakness of the WD kicks, such warmed FFPs can thus be associated with their former host stars for several Myr after formation. Therefore, WD formation kicks contribute a distinct, observationally identifiable FFP sub-population comprising a few percent of the Galaxy's FFPs, relevant for the design of future FFP surveys.
Comments7 pages, 6 figures, submitted to ApJL
