Astronomers Find Rocky Exoplanet with Atmosphere in Habitable Zone

Astronomers have identified a rocky exoplanet, designated TOI‑1234 b, that possesses a measurable atmosphere and resides within the habitable zone of its host star. The planet orbits a G‑type star roughly 300 light‑years from Earth, completing a full orbit every 18.4 days. Spectroscopic analysis of the star’s transits revealed absorption features consistent with a mix of nitrogen, oxygen, and trace water vapor, suggesting a potentially Earth‑like atmospheric composition.

The discovery was made using data from the Transiting Exoplanet Survey Satellite (TESS) combined with follow‑up observations from the Hubble Space Telescope’s Wide Field Camera 3. Researchers noted the planet’s radius is about 1.2 times that of Earth, and its mass—derived from radial‑velocity measurements—implies a rocky interior with a surface gravity only slightly higher than Earth’s. The equilibrium temperature, calculated from the planet’s distance and stellar luminosity, falls within the range that could allow liquid water to exist on its surface, placing TOI‑1234 b among the most promising candidates for further atmospheric characterization.

While the presence of an atmosphere does not guarantee habitability, the planet’s size, composition, and position in the habitable zone make it a prime target for upcoming missions such as the James Webb Space Telescope and the European Space Agency’s ARIEL mission. Continued observations will aim to refine atmospheric models and search for biosignature gases, advancing the search for potentially life‑bearing worlds beyond our solar system.