TESS Visible Phase Curves Indicate Elevated Geometric Albedos in Ultra-Hot Rocky Exoplanets
What Was Observed (Empirical Data)
Using visible-light phase curve photometry from NASA's TESS mission, researchers achieved greater than 3-sigma detections of optical phase variation for LTT 9779 b and five lava worlds: TOI-2431 b, TOI-561 b, 55 Cancri e, K2-141 b, and TOI-1444 b. Combining these detections with archival data from Kepler and CHEOPS, the team derived geometric albedos showing that these sub-5 Earth-radii planets are systematically more reflective than hot Jupiters at comparable equilibrium temperatures. The elevated optical reflectance indicates that cooler-than-expected dayside temperatures are driven by reflective dayside clouds, likely condensed silicates, rather than solely by atmospheric heat circulation.
The Reality Check (Anti-Hype Analysis)
These measurements do not imply temperate environments, water, or habitability; these planets remain intensely irradiated, tidally locked hellscapes hot enough to vaporize and melt rock. Furthermore, broadband photometric phase curves alone cannot uniquely identify cloud mineralogy or definitively rule out complex surface-reflection physics without future high-resolution spectroscopic validation.
PRIMARY SOURCE:
arXiv Astrophysics (astro-ph)