TRAPPIST-1 f, g, and h may have subsurface oceans and detectable cryovolcanic water vapor

Star system: TRAPPIST-1 | Distance from the Sun: 40.7 light years

Scientists modeled the interiors and atmospheres of the exoplanets TRAPPIST-1f, g, and h to see if they could sustain subsurface oceans and produce detectable water vapor through cryovolcanism. Using simulations, they found that all three planets’ internal heat is mainly generated by radioactive decay and tidal forces. TRAPPIST-1f and g are likely to have thin outer ice shells and shallow subsurface oceans, while TRAPPIST-1h may have a thicker ice shell.

The study shows that localized cryovolcanic plumes would create stronger infrared signals than a globally spread exosphere, making them more detectable by telescopes like JWST. Under favorable conditions, water vapor outgassing on TRAPPIST-1f could be detected after about 20 transits. The results suggest that subsurface oceans are possible on all three planets, and that the amount and location of outgassed water are key to its detectability. This research provides a framework for future studies of Europa-like exoplanets and their potential for hosting water.

Key findings
- TRAPPIST-1f, g, and h can sustain subsurface oceans under a range of conditions.
- Internal heat comes mainly from radiogenic and tidal sources.
- Thin ice shells and shallow oceans are likely for f and g; h may have a thicker shell.
- Localized cryovolcanic plumes are more detectable than global exospheres.
- Water vapor outgassing on TRAPPIST-1f could be detected with JWST after about 20 transits.

Scientific study

Interior-Atmosphere Coupling on TRAPPIST-1 f, g, and h: Cryovolcanic Water Exospheres and Infrared Detectability (external link)