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arXiv 1005.2186astro-ph.EP
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潮汐演化和蒸发质量损失在CoRoT-7 b形成中的作用

The Roles of Tidal Evolution and Evaporative Mass Loss in the Origin of CoRoT-7 b

Brian Jackson, Neil Miller, Rory Barnes, Sean N. Raymond, Jonathan Fortney, Richard Greenberg

摘要:

CoRoT-7 b是第一颗被证实的岩质系外行星,但它的轨道半长轴为0.0172 AU,它的起源可能不同于我们太阳系中的任何岩质行星。在这项研究中,我们考虑了潮汐演化和蒸发质量损失在CoRoT-7 b历史中的作用,它们共同改变了行星的质量和轨道。如果CoRoT-7 b一直是一个岩石天体,蒸发可能已经带走了它几乎一半的原始质量,但质量损失可能敏感地取决于它轨道的潮汐衰变程度。当潮汐导致CoRoT-7 b的轨道衰减时,它们使这颗行星更接近它的主星,从而提高了质量损失率。如此大的质量损失也表明,CoRoT-7 b可能最初是一颗气态巨行星,其原始大气层完全蒸发。在这种情况下,我们发现CoRoT-7 b的原始质量可能不超过200个地球质量(约为木星质量的2/3)。这颗行星在主星上引起的潮汐可能显著地减小了轨道半长轴,可能导致这颗行星通过与系统中另一颗行星CoRoT-7 c的平均运动共振而迁移。潮汐演化和质量损失之间的耦合可能不仅对CoRoT-7 b而且对其他近距离系外行星都很重要,未来对质量损失和轨道演化的研究可能会深入了解近距离行星的起源和命运,包括岩石和气体。

英文摘要:

CoRoT-7 b is the first confirmed rocky exoplanet, but, with an orbital semi-major axis of 0.0172 AU, its origins may be unlike any rocky planet in our solar system. In this study, we consider the roles of tidal evolution and evaporative mass loss in CoRoT-7 b's history, which together have modified the planet's mass and orbit. If CoRoT-7 b has always been a rocky body, evaporation may have driven off almost half its original mass, but the mass loss may depend sensitively on the extent of tidal decay of its orbit. As tides caused CoRoT-7 b's orbit to decay, they brought the planet closer to its host star, thereby enhancing the mass loss rate. Such a large mass loss also suggests the possibility that CoRoT-7 b began as a gas giant planet and had its original atmosphere completely evaporated. In this case, we find that CoRoT-7 b's original mass probably didn't exceed 200 Earth masses (about 2/3 of a Jupiter mass). Tides raised on the host star by the planet may have significantly reduced the orbital semi-major axis, perhaps causing the planet to migrate through mean-motion resonances with the other planet in the system, CoRoT-7 c. The coupling between tidal evolution and mass loss may be important not only for CoRoT-7 b but also for other close-in exoplanets, and future studies of mass loss and orbital evolution may provide insight into the origin and fate of close-in planets, both rocky and gaseous.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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