Noto Daisuke, Miyagoshi Takehiro, Terada Tomomi, Yanagisawa Takatoshi, Tasaka Yuji
Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, USA.
Research Institute for Value-Added-Information Generation, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan.
Nat Commun. 2025 Jul 25;16(1):6846. doi: 10.1038/s41467-025-62026-z.
Tidal locking imposes distinctive thermal forcing on super-Earth exoplanets in habitable zones, i.e., permanent stellar flux forces extraordinary day-night temperature contrast. However, it may be premature to conclude that life is absent in such supposedly harsh environments-flaming hot on dayside and freezing cold on nightside-when accounting for unobservable features, such as internal convective dynamics and their consequential impact on the surface environment. We establish a simplistic but canonical framework scalable for modeling the convective dynamics in the mantle of tidally-locked exoplanets. The laboratory experiments unveiled an everlasting system-scale circulation that localizes mass and heat transport inside the mantle for a wide range of parameters. We identified the governing parameters that characterize the mass and heat transport of the system and demonstrated their significance. The permanently anchored internal convective structures will be integrated as extraordinary tectonic and deep core activities that differ substantially from those on Earth. In particular, a gradually varying heat flux distribution from the substellar to antistellar points hints at the presence of liquid water in the mid- to high-latitudes due to their moderate geothermal heating, which can potentially host and nurture life on such faraway worlds.
潮汐锁定对宜居带中的超级地球系外行星施加了独特的热强迫，即持续的恒星通量导致了异常的昼夜温度差异。然而，在考虑诸如内部对流动力学及其对表面环境的后续影响等不可观测特征时，就得出在这种看似恶劣的环境（白天酷热，夜晚严寒）中不存在生命的结论，可能为时过早。我们建立了一个简单但规范的框架，可扩展用于模拟潮汐锁定系外行星地幔中的对流动力学。实验室实验揭示了一个持久的系统规模循环，该循环在广泛的参数范围内将质量和热量传输定位在地幔内部。我们确定了表征系统质量和热量传输的控制参数，并证明了它们的重要性。永久固定的内部对流结构将作为异常的构造和深部核心活动整合在一起，这些活动与地球上的活动有很大不同。特别是，从恒星到反恒星点的热通量分布逐渐变化，这表明中高纬度地区存在液态水，因为它们有适度的地热加热，这可能在这些遥远的世界上孕育和滋养生命。
