A New Model of Roche Lobe Overflow for Short-period Gaseous Planets and Binary Stars
A New Model of Roche Lobe Overflow for Short-period Gaseous Planets and Binary Stars
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短周期气态行星和双星罗氏瓣溢出的新模型
DOI：
10.3847/1538-4357/835/2/145
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
P. Marchant
中科院分区：
文献类型：
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作者：
B. Jackson;P. Arras;K. Penev;S. Peacock;P. Marchant
一些靠近的气态系外行星几乎处于洛希瓣接触状态，先前的研究表明，潮汐衰变可以在其宿主恒星的主序期间驱动热的彗星接触。改进以前的模型，我们提出了一个修正的模型，在一个半分离的二元系统，采用了扩展的气氛周围的捐助者，并允许一个任意的质量比的传质。我们应用这种新的形式主义假设，确认，和候选行星系统估计质量损失率和蒸发质量损失模型进行比较。对于热海王星来说，溢出可能会在202天内很重要，而对于热海王星来说，它可能只在0.5天内很重要。我们发现CoRoT-24 B可能以超过地球质量的速度在十亿年内失去质量。热木星WASP-12 B可能会在一个百万年内失去一个地球的质量，而假定的行星PTFO 8 -8695绕着一颗金牛座T星星运行，可能会在几个百万年内失去它的大气层。我们指出，轨道膨胀，可以伴随着质量转移可能是不太有效的比以前考虑的，因为由主机星星吸积的气体从轨道上删除了一些角动量，但简单的缩放参数表明，罗氏瓣溢出可能保持稳定。因此，最近发现的超短周期（<1天）的小行星可能不是热彗星/海王星的残余。这里提出的新模型已被纳入恒星天体物理学实验模块（梅萨）。
Some close-in gaseous exoplanets are nearly in Roche lobe contact, and previous studies show that tidal decay can drive hot Jupiters into contact during the main sequence of their host stars. Improving on a previous model, we present a revised model for mass transfer in a semidetached binary system that incorporates an extended atmosphere around the donor and allows for an arbitrary mass ratio. We apply this new formalism to hypothetical, confirmed, and candidate planetary systems to estimate mass-loss rates and compare with models of evaporative mass loss. Overflow may be significant for hot Neptunes out to periods of ∼2 days, while for hot Jupiters, it may only be important inward of 0.5 days. We find that CoRoT-24 b may be losing mass at a rate of more than an Earth mass in a gigayear. The hot Jupiter WASP-12 b may lose an Earth mass in a megayear, while the putative planet PTFO8-8695 orbiting a T Tauri star might shed its atmosphere in a few megayears. We point out that the orbital expansion that can accompany mass transfer may be less effective than previously considered because the gas accreted by the host star removes some of the angular momentum from the orbit, but simple scaling arguments suggest that the Roche lobe overflow might remain stable. Consequently, the recently discovered small planets in ultrashort periods (<1 day) may not be the remnants of hot Jupiters/Neptunes. The new model presented here has been incorporated into Modules for Experiments in Stellar Astrophysics (MESA).