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The coevolution of migrating planets and their pulsating stars through episodic resonance locking
Nature Astronomy ( IF 12.9 ) Pub Date : 2024-09-17 , DOI: 10.1038/s41550-024-02351-3
Jared Bryan, Julien de Wit, Meng Sun, Zoë L. de Beurs, Richard H. D. Townsend

Hot Jupiters are expected to form far from their host star and move to a close-in, circular orbit through a smooth, monotonic decay due to mild and constant tidal dissipation. Yet, systems exhibiting planet-induced stellar pulsations have recently been found, suggesting unexpectedly strong tidal interactions. Here we combine stellar evolution and tide models to show that dynamical tides raised by eccentric gas giants can excite chains of resonance locks with several modes, which enriches the dynamics seen in single-mode resonance locking of circularized systems. These series of resonance locks yield orders of magnitude larger changes in eccentricity and harmonic pulsations relative to those expected from a single episode of resonance locking or non-resonant tidal interactions. Resonances become more frequent as a star evolves off the main sequence, which provides an alternative explanation for the origin of some stellar pulsators and leads to the concept of ‘dormant migrating giants’. Evolution trajectories are characterized by competing episodes of inward and outward migration and the spin-up or spin-down of the star, which are sensitive to the system parameters. This is a new challenge in modelling migration paths and in contextualizing the observed populations of giant exoplanets and stellar binaries. This sensitivity, however, offers a new window for constraining the stellar properties of planetary hosts through tidal asteroseismology.



中文翻译:


迁移行星及其脉动恒星通过情景共振锁定的共同演化



预计热木星将在远离其主恒星的地方形成,并由于温和且持续的潮汐耗散而通过平滑、单调的衰变移动到近距离的圆形轨道。然而,最近发现了表现出行星引起的恒星脉动的系统,这表明存在意想不到的强烈潮汐相互作用。在这里,我们将恒星演化和潮汐模型结合起来,证明偏心气态巨行星引发的动力潮汐可以激发具有多种模式的共振锁链,这丰富了圆形系统的单模式共振锁定的动力学。相对于单次共振锁定或非共振潮汐相互作用所预期的变化,这一系列共振锁定产生的偏心率和谐波脉动的变化要大几个数量级。随着恒星从主序带演化出来,共振变得更加频繁,这为一些恒星脉动器的起源提供了另一种解释,并引出了“休眠的迁移巨星”的概念。演化轨迹的特点是向内和向外迁移以及恒星自旋向上或自旋向下的竞争事件,这些对系统参数很敏感。这是对迁移路径进行建模以及将观测到的巨型系外行星和恒星双星种群置于背景中的新挑战。然而,这种敏感性为通过潮汐星震学限制行星宿主的恒星特性提供了一个新的窗口。

更新日期:2024-09-17
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