Scientists have discovered the strongest evidence yet of an atmosphere on a molten rocky exoplanet, challenging existing theories about planetary formation and habitability. The exoplanet, TOI-561 b, is a super-Earth with a radius 1.4 times that of Earth, orbiting a Sun-like star approximately 275 light-years away. This planet is part of a rare class of ultra-short period (USP) exoplanets, completing an orbit in less than 11 hours. Observations from the James Webb Space Telescope's Near-Infrared Spectrometer (NIRSpec) suggest that TOI-561 b is covered by a global magma ocean, with a thick atmosphere above it. This discovery raises questions about the planet's ability to maintain an atmosphere despite its proximity to its star and the intense radiation it receives. The research team, led by Johanna Teske, found that TOI-561 b's atmosphere is likely composed of volatile gases, including water vapor, which absorb certain wavelengths of near-infrared light, making the planet appear cooler than expected. The planet's low density and potential small iron core further support the idea of a thick atmosphere, as it suggests a composition different from that of the Earth. The findings, published in The Astrophysical Journal Letters, open new avenues for understanding planetary atmospheres and the conditions necessary for their formation.
