Hot Jupiters — gas giants on close-in orbits — have unexpectedly large radii. A new study refines their thermal evolution model by accounting for heating both in the interior and at the surface. A Bayesian analysis showed the cooling rate is reduced by 95–98% — pointing to strong surface heating just below the convection boundary. Think of it like the planet being 'heated' not so much from within, but from under the 'lid' of its atmosphere. If that’s the case, the observed wind patterns should peak at temperatures between 1500 and 1800 K.
Hot Jupiters—exoplanets giants snuggled up to their stars—are mysteriously puffed up. Their radii often exceed standard models by 50–100%. New models, based on transiting data (transit method), flip our understanding: heat doesn't come from the interior but from the upper atmosphere. Think of soup: if you heat only the surface, a thin layer boils while the rest stays cool. Similarly, heat gets trapped at the top, slowing interior cooling by 95–98%. This swelling can persist for eons. Even wilder: at 1500°C winds whip up, but at 1800°C they abruptly stop—like the planet overheats and turns off its own storm.
🎯 Some hot Jupiters complete an orbit around their star in less than an Earth day—on such a planet, a year is shorter than a day!