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arXiv 1902.02103astro-ph.EP
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海洋动力学与潮汐闭锁类地行星适宜居带的内缘

Ocean Dynamics and the Inner Edge of the Habitable Zone for Tidally Locked Terrestrial Planets

Jun Yang, Dorian S. Abbot, Daniel D. B. Koll, Yongyun Hu, Adam P. Showman

摘要:

最近的研究表明,海洋动力学可以对永久性的夜晚产生显著的变暖效应,这些夜晚是1比1潮汐锁定的类地系外行星,在宜居带中间有类似地球的大气和海洋。然而,海洋动力学对宜居带边界(内缘和外缘)的影响仍然是未知的,这是我们对这类行星理解的一个主要空白。在这里,我们使用一个耦合的大气-海洋全球气候模式,以显示行星的热量传输从白天到黑夜的一面是由海洋在较低的恒星通量和大气附近的宜居带的内边缘。在高恒星通量下,海洋热传输(OHT)的减少主要是由于表面风应力的减弱和表面短波能量沉积的减少。我们进一步表明,海洋动力学几乎没有影响的观测热相位曲线的行星附近的内边缘的宜居带。对于行星在宜居带的中间范围,海洋动力学移动最热点的表面从亚恒星点向东。这些结果表明,未来对内缘的研究可能会将计算资源投入到仅限于大气的过程中,如云和辐射。然而,对于宜居带的中间范围和外缘的研究,将需要完全耦合的海洋-大气模拟。请注意,由于计算资源的限制,只有一个旋转周期(60个地球日)已在本研究中系统地检查;未来的工作,不同的旋转周期以及其他参数,如大气质量和成分是必要的。

英文摘要:

Recent studies have shown that ocean dynamics can have a significant warming effect on the permanent night sides of 1 to 1 tidally locked terrestrial exoplanets with Earth-like atmospheres and oceans in the middle of the habitable zone. However, the impact of ocean dynamics on the habitable zone's boundaries (inner edge and outer edge) is still unknown and represents a major gap in our understanding of this type of planets. Here we use a coupled atmosphere-ocean global climate model to show that planetary heat transport from the day to night side is dominated by the ocean at lower stellar fluxes and by the atmosphere near the inner edge of the habitable zone. This decrease in oceanic heat transport (OHT) at high stellar fluxes is mainly due to weakening of surface wind stress and a decrease in surface shortwave energy deposition. We further show that ocean dynamics have almost no effect on the observational thermal phase curves of planets near the inner edge of the habitable zone. For planets in the habitable zone's middle range, ocean dynamics moves the hottest spot on the surface eastward from the substellar point. These results suggest that future studies of the inner edge may devote computational resources to atmosphere-only processes such as clouds and radiation. For studies of the middle range and outer edge of the habitable zone, however, fully coupled ocean-atmosphere modeling will be necessary. Note that due to computational resource limitations, only one rotation period (60 Earth days) has been systematically examined in this study; future work varying rotation period as well as other parameters such as atmospheric mass and composition is required.

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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