Five scorched, ultra-short-period rocky worlds are the test cases: models show most end up as bare rock, with global melt fractions capping out at 20% or less. One gas, S2, spikes when the surface is solid rather than molten, giving JWST a possible tracer to tell which interior state a planet is really in before its atmosphere burns away.

— via arXiv — Astro-ph, Mariana Sastre, Tim Lichtenberg, Lisa Dang, Anjali Piette, Haiyang S. Wang, Mercedes L'opez-Morales, Thomas Wilson, Charles-'Edouard Boukar'e, Mahesh Herath, Nicolas Cowan, Md Abdullah Al Zaman, Madyson G. Barber, Casey Brinkman-Traverse, Nicholas Connors, Ian Crossfield, Lina D'Aoust, Oliver Herbort, Leoni Janssen, Mathilde Kervazo, Owen Lammert, Yamila Miguel, Raymond Pierrehumbert, Allona Vazan, Joost P. Wardenier, Sebastian Zieba