Astronomers detect dense atmosphere on distant rocky exoplanet

Astronomers have detected signs of an atmosphere on the rocky exoplanet TOI-561 b, previously thought to be too hot and small to retain a gaseous envelope, ScienceDaily reported on March 22.

TOI-561 b is a super-Earth with roughly twice the mass of Earth. It orbits so close to its star that it completes a full rotation in just 10.5 hours, with one side permanently facing the star.

Previously, scientists believed such extreme conditions would strip the planet of its atmosphere. However, new observations show the dayside temperature is significantly lower than expected for a bare rocky surface—around 1800 °C instead of the predicted 2700 °C. Researchers attribute this discrepancy to heat redistribution, which is only possible with a dense gaseous envelope.

Scientists suggest that TOI-561 b may be a “lava world,” with a magma-covered surface and an atmosphere maintained through material exchange between the gaseous envelope and the planet’s interior layers. This dynamic allows the planet to retain its atmosphere despite intense stellar radiation.

The researchers describe TOI-561 b as a potential “wet lava ball” with active atmospheric processes, strong winds, and possible cloud formation from silicate particles.