rocketsocks t1_jda2reu wrote
Reply to comment by lezboyd in James Webb Space Telescope spies hot, gritty clouds on exoplanet with 2 suns by tkocur
The planet in question is on the borderline of being almost massive enough to be classified as a brown dwarf. Just like proto-stars and brown dwarfs, planets receive a great deal of heating from accretion and gravitational contraction. And due to the square-cube law the more massive an object is the more of this energy is released and the longer it is retained because surface area grows more slowly than volume. The result is that there is a great deal of internal heat that is retained within gas giants, especially the more massive ones.
EarthSolar t1_jda578n wrote
It’s also really, really young, at 140 million years according to Wikipedia. Jovian worlds and brown dwarfs form hot, and at young age they can be as hot as the coolest stars at ~2000-3000 Kelvins. They cool over time, but the rate is slowed from what you’d normally expect due to gravitational contraction converting planet mass’ gravitational potential energy into thermal energy as the planet shrinks down.
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