Astronomers have identified signs of an atmosphere on the rocky exoplanet HD 3167 b, located 154 light-years from Earth. The planet orbits its star in one Earth day, with its day side likely covered in molten rock. The study was led by the University of Chicago using the James Webb Space Telescope and published in The Astrophysical Journal Letters.
Researchers utilized the secondary eclipse method to measure infrared radiation changes, revealing that the planet's day side is cooler than expected. This suggests the presence of an atmosphere that redistributes heat to the night side, or clouds that reflect stellar radiation. HD 3167 b is currently the coldest known lava world with evidence of an atmosphere.
While the exact composition remains unknown, scientists suggest it could contain heavy gases like carbon dioxide, carbon monoxide, or water vapor, rather than just vaporized rock. This research is part of a broader program observing ten ultra-hot lava planets to determine the conditions under which rocky worlds develop dense atmospheres or silicate clouds.
Studying these lava worlds provides insights into Earth's early history, as the planet may have been a magma ocean shortly after its formation. Observations of these super-Earths help researchers understand how young rocky planets form and retain their gaseous envelopes despite intense stellar radiation and wind.
