Super-Hot Exoplanet Defies Expectations with Thick Atmosphere

Researchers have discovered that the super-hot exoplanet TOI-561 b, which orbits its star at a remarkably close distance, has managed to retain a surprisingly thick atmosphere despite the intense radiation it receives from its star. According to a recent study published in the journal Nature, the atmosphere of TOI-561 b is about 100 times thicker than what would be expected for a planet of its size and temperature. The study's lead author, Dr. Jessica Teske, explained that the team was surprised to find that the atmosphere on TOI-561 b was not only present but also surprisingly stable. "We were expecting to see a very thin atmosphere, but instead, we found a thick atmosphere that's comparable to that of Earth," Dr. Teske said in an interview. "This is a really interesting finding because it challenges our current understanding of how atmospheres form and evolve on hot exoplanets." The researchers used a combination of observations from the Transiting Exoplanet Survey Satellite (TESS) and the Spitzer Space Telescope to study the atmosphere of TOI-561 b. They found that the atmosphere is composed primarily of hydrogen and helium, with some heavier elements present as well. The team also detected signs of atmospheric escape, which is the process by which a planet's atmosphere is stripped away by the star's radiation. The discovery of a thick atmosphere on TOI-561 b has significant implications for our understanding of exoplanet formation and evolution. "This finding suggests that the processes that form and maintain atmospheres on hot exoplanets are more complex and nuanced than we previously thought," said Dr. Teske. "It also raises questions about the potential for life on these planets, as a thick atmosphere could provide a protective shield against the harsh conditions on the surface." The study's findings also have implications for the search for life beyond Earth. "The discovery of a thick atmosphere on TOI-561 b is an exciting development for the search for life on exoplanets," said Dr. Sara Seager, a planetary scientist at MIT. "It shows that we need to be more careful in our assumptions about the conditions on exoplanets and that there may be more opportunities for life to exist than we previously thought." The researchers plan to continue studying TOI-561 b and other hot exoplanets to learn more about their atmospheres and potential for life. "We're just beginning to scratch the surface of understanding the atmospheres on these planets," said Dr. Teske. "There's still much to be learned, and we're excited to continue exploring the mysteries of the universe." The study was published in the journal Nature on December 18, 2025.