Abstract Lava planets likely did not form in their current orbits, instead migrating inward via orbital decay, which influenced the evolution of their magma oceans. We introduce a coupled thermal–orbital evolution model to explore how rocky planets migrate from the inner edge of the protoplanetary disk, with periods of 1–10 days, to orbital periods of less than 1 day. In our model, mantle melting is controlled by tidal heating and stellar flux, while orbits evolve via tidal migration. The mantle’s tidal quality factor varies with its temperature and structure, creating a feedback loop between thermal evolution and orbital decay. We use our numerical model to simulate the migration of seven known lava planets: K2-141b, K2-360b, TOI-141b, TOI-431b, TOI-2431b, HD 3167b, and GJ 367b. Migration occurs in two stages: an initial high-eccentricity stage reducing the semimajor axis by a factor of ∼2, followed by a low-eccentricity stage reducing it by a factor of ∼5. A successful migration from ∼0.1 au to a present-day orbit requires starting eccentricities ≥0.9 and sustained eccentricity forcing with e min ≥ 1 0 − 2 . The rate of migration depends on the state of the mantle: slow when mostly molten, fast when mostly solid. This pathway works for most lava planets, but not for TOI-431b or GJ 367b, suggesting that multiple migration pathways are possible for lava planets.
Herath et al. (Tue,) studied this question.