Moons orbiting wandering exoplanets could be habitable—with one catch
Why it matters: This expands the search for life beyond star systems, suggesting habitable worlds could be drifting through space.
- David Dahlbüdding (Max Planck Institute for Extraterrestrial Physics) and Giulia Roccetti (European Space Agency) led a study predicting that hydrogen-rich atmospheres could make exomoons habitable.
- Tidal forces generated by the host planet's gravity could create vast amounts of internal heat within these moons, similar to Europa and Enceladus.
- High-pressure hydrogen atmospheres can absorb heat through "collision-induced absorption" (CIA), rivaling potent greenhouse gases like carbon dioxide and methane, preventing heat from radiating into space.
- Previous studies have explored how thick hydrogen atmospheres could efficiently trap energy, potentially leading to surface temperatures sufficient for liquid water without a nearby star.
- Dahlbüdding notes that while such exomoons might be detectable soon, confirming and analyzing their atmospheres will remain a long-term challenge.
Moons orbiting rogue exoplanets, ejected from their star systems, could surprisingly harbor habitable conditions for billions of years if they possess thick, hydrogen-dominated atmospheres. A new study by David Dahlbüdding and Giulia Roccetti suggests that hydrogen, under high pressure, acts as a powerful greenhouse gas, trapping internal tidal heat and potentially maintaining liquid water on these otherwise frigid worlds.
