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 a 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 semi-major 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 emin≥10−2.
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.
Mahesh Herath, Nicolas B. Cowan, Charles-Édouard Boukaré, Mathieu Dumberry
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2604.18682 [astro-ph.EP] (or arXiv:2604.18682v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2604.18682
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Submission history
From: Mahesh Herath
[v1] Mon, 20 Apr 2026 18:00:02 UTC (5,509 KB)
https://arxiv.org/abs/2604.18682
Astrobiology,
