04-28-2025, 07:05 PM
From the 'bonus' link above;
Quote:We find that the observed atmospheric CH4/CO2 ratio implies a minimum ocean temperature of ~710 K, whereas the corresponding CO/CO2 ratio allows ocean temperatures up to ~1070 K. These results indicate that a global supercritical water ocean on K2-18 b is plausible. While life cannot survive in such an ocean, this work represents the first step toward understanding how a global supercritical water ocean may influence observable atmospheric characteristics on volatile-rich sub-Neptunes.This seems more likely than a magma ocean to me, but we should include examples of both in OA. Neither type seems very hospitable to colonisation, unless you can build a suprashell above the atmosphere.