Lava planet has hydrogen-rich, active atmosphere

Scientists have used NASA’s James Webb Space Telescope to study 55 Cancri e, an exoplanet located about 41 light-years away. The planet, classified as a super Earth, is tidally locked to its star and completes an orbit in just 0.7 days, leading researchers to believe its surface is partially or fully molten.

The study, which analyzed five eclipses of the planet, found that 55 Cancri e’s atmosphere is likely rich in carbon monoxide and hydrogen, with smaller amounts of carbon dioxide. The data also suggests possible outgassing or cloud formation, which could temporarily cool the surface before being pushed away by volcanic activity.

The research, submitted for publication in Nature Astronomy, highlights the link between a planet’s interior composition and its atmosphere. The hydrogen-rich nature of 55 Cancri e suggests a low oxygen fugacity in its interior, consistent with outgassing from a reduced magma ocean. This finding could help scientists better understand how lava exoplanets form and evolve.

Lava exoplanets, such as 55 Cancri e, K2-141 b, and CoRoT-7 b, are known for their extreme temperatures and volcanic activity. Unlike Io, which experiences tidal heating, these exoplanets are heated by their close orbits around their stars. As research continues, scientists hope to uncover more about the atmospheres and internal structures of these extreme worlds.