The Sub-Neptune Desert · Hot-Neptune Gap
unseel.com · period–radius plane · photoevaporation · high-e migration
Regime P ≲ 3 d
Divide M ≈ 0.2 M_J
Engine
Host star (XUV)
Neptune envelope
Escaping gas / tidal limit
Stripped super-Earth
Empty desert
Unseel.com · The Sub-Neptune Desert: Two Rival Engines Behind the Hot-Neptune Gap