http://arxiv.org/abs/1912.02862
The presence of a liquid solvent is widely regarded as an essential prerequisite for habitability. We investigate the conditions under which worlds outside the habitable zones of stars are capable of supporting liquid solvents on their surface over geologically significant timescales via combined radiogenic and primordial heat. Our analysis suggests that super-Earths with radionuclide abundances that are $\gtrsim 10^3$ times higher than Earth can host long-lived water oceans. In contrast, the requirements for long-lived ethane oceans, which have been explored in the context of alternative biochemistries, are less restrictive: relative radionuclide abundances of $\gtrsim 10^2$ could be sufficient. At such radionuclide levels, we find that these worlds may be detectable ($10\sigma$ detection over $\sim 10$ days integration time at $12.8$ $\mu$m) by the James Webb Space Telescope at distances of $\sim 10$ pc if their ages are $\lesssim 1$ Gyr.
M. Lingam and A. Loeb
Mon, 9 Dec 19
19/53
Comments: 7 pages; 4 figures