标题： 围绕M型星的类地系外行星的潮汐加热：热、磁和轨道演化 显示英文标题

标题： Tidal heating of Earth-like exoplanets around M stars: Thermal, magnetic, and orbital evolutions

摘要： 岩石系外行星的内部热和磁场演化对其可居住性至关重要。 我们关注围绕低质量M型恒星的地球质量行星的热-轨道演化，这些恒星的辐射可居住区与“潮汐区”重叠。 我们开发了一个校准到地球的热-轨道演化模型，该模型将潮汐耗散与温度依赖的Maxwell流变学耦合到轨道圆化和迁移。 我们展示了热-轨道稳态情况，在这种情况下，地表热流被潮汐耗散平衡，冷却可以停滞数十亿年，直到圆化发生。 作为潮汐热耗散在内部的轨道能量驱动向内迁移和圆化，圆化时间与耗散率成反比。 我们发现当地幔通过接近1800 K的地幔温度的粘弹性状态时，内部耗散率有一个峰值。围绕0.1倍太阳质量的恒星在$0.07$ AU以内的行星在10 Gyr内圆化，与初始偏心率无关。 一旦圆化，这些行星单调冷却，并保持类似于地球的发电机。 被强制进入偏心轨道的行星可能会经历核心的超冷和快速核心固化，从而抑制宜居带内行星的发电机作用。 我们发现，在$0.45$ (或更大)倍太阳质量恒星的宜居带内，潮汐加热是微不足道的，因为潮汐耗散对轨道距离的依赖比恒星质量更强，而宜居带离大质量恒星更远。 行星磁场的抑制使大气暴露于恒星风侵蚀，表面暴露于有害辐射。 除了弱磁场外，大量的熔岩喷发速率和长时间的岩浆海洋可能使低质量恒星宜居带内的偏心行星不适合生命存在。 显示英文摘要

摘要： The internal thermal and magnetic evolution of rocky exoplanets is critical to their habitability. We focus on the thermal-orbital evolution of Earth-mass planets around low mass M stars whose radiative habitable zone overlaps with the "tidal zone". We develop a thermal-orbital evolution model calibrated to Earth that couples tidal dissipation, with a temperature-dependent Maxwell rheology, to orbital circularization and migration. We illustrate thermal-orbital steady states where surface heat flow is balanced by tidal dissipation and cooling can be stalled for billions of years until circularization occurs. Orbital energy dissipated as tidal heat in the interior drives both inward migration and circularization, with a circularization time that is inversely proportional to the dissipation rate. We identify a peak in the internal dissipation rate as the mantle passes through a visco-elastic state at mantle temperatures near 1800 K. Planets orbiting a 0.1 solar-mass star within $0.07$ AU circularize before 10 Gyr, independent of initial eccentricity. Once circular, these planets cool monotonically and maintain dynamos similar to Earth. Planets forced into eccentric orbits can experience a super-cooling of the core and rapid core solidification, inhibiting dynamo action for planets in the habitable zone. We find that tidal heating is insignificant in the habitable zone around $0.45$ (or larger) solar mass stars because tidal dissipation is a stronger function of orbital distance than stellar mass, and the habitable zone is further from larger stars. Suppression of the planetary magnetic field exposes the atmosphere to stellar wind erosion and the surface to harmful radiation. In addition to weak magnetic fields, massive melt eruption rates and prolonged magma oceans may render eccentric planets in the habitable zone of low mass stars inhospitable for life.