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The internal thermal and magnetic evolution of rocky exoplanets is criticalto their habitability. We focus on the thermal-orbital evolution of Earth-massplanets around low mass M stars whose radiative habitable zone overlaps withthe "tidal zone". We develop a thermal-orbital evolution model calibrated toEarth that couples tidal dissipation, with a temperature-dependent Maxwellrheology, to orbital circularization and migration. We illustratethermal-orbital steady states where surface heat flow is balanced by tidaldissipation and cooling can be stalled for billions of years untilcircularization occurs. Orbital energy dissipated as tidal heat in the interiordrives both inward migration and circularization, with a circularization timethat is inversely proportional to the dissipation rate. We identify a peak inthe internal dissipation rate as the mantle passes through a visco-elasticstate at mantle temperatures near 1800 K. Planets orbiting a 0.1 solar-massstar within $0.07$ AU circularize before 10 Gyr, independent of initialeccentricity. Once circular, these planets cool monotonically and maintaindynamos similar to Earth. Planets forced into eccentric orbits can experience asuper-cooling of the core and rapid core solidification, inhibiting dynamoaction for planets in the habitable zone. We find that tidal heating isinsignificant in the habitable zone around $0.45$ (or larger) solar mass starsbecause tidal dissipation is a stronger function of orbital distance thanstellar mass, and the habitable zone is further from larger stars. Suppressionof the planetary magnetic field exposes the atmosphere to stellar wind erosionand the surface to harmful radiation. In addition to weak magnetic fields,massive melt eruption rates and prolonged magma oceans may render eccentricplanets in the habitable zone of low mass stars inhospitable for life.

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