Free-Floating Exomoons: Tidal Heating and Hydrogen Atmospheres Sustain Sunless Oceans

To the point

Moons around free-floating interstellar planets could host long-lasting habitable oceans without sunlight, kept warm by tidal heating and a hydrogen-rich atmosphere that traps heat, potentially sustaining liquid water for billions of years and enabling prebiotic chemistry, as proposed by David Dahlbüdding, Tommaso Grassi, Karan Molaverdikhani, Giulia Roccetti, Barbara Ercolano, Dieter Braun, and Paola Caselli.