K2-18b life?

[AstroChara]

From the 'bonus' link above;

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.

A lot of rocks wouldn't melt until higher temperatures, although there isn't any issue with supercritical water interacting with magma ocean. The thing that sets it apart from the magma ocean model is that there is the supercritical water layer, I believe? Not sure.