Astronomers have significantly improved the search for life beyond Earth by identifying **45 rocky exoplanets** out of more than 6,000 known planets. These planets are the most likely candidates to be habitable. The study, led by Professor **Lisa Kaltenegger** and undergraduate students at the Carl Sagan Institute at Cornell University, was published in *Monthly Notices of the Royal Astronomical Society* on March 19, 2026.
Using updated data from ESA’s Gaia mission and the NASA Exoplanet Archive, the team filtered out rocky planets (those with a radius less than twice the Earth’s radius or a mass less than five times the Earth’s mass) that orbited within the **empirical habitable zone** — the orbital region where liquid water can exist on the surface, and its boundaries are set based on the planets Venus and Mars. A more rigorous “3D habitable zone” model, which included more conservative assumptions about heat from the star and atmospheric effects, further reduced the list to **24 planets**.
Many of these candidates orbit smaller, cooler red dwarf stars, making them easier to see because these stars are less luminous and their transits provide clearer signals. Some planets lie 40–50 light-years away, including the planets of the TRAPPIST-1 system and well-known planets such as Proxima Centauri b, Kepler-186 f, and LHS 1140 b. This list prioritizes planets that are near the edge of the habitable zone, that receive Earth-like radiation from stars, and that have eccentric orbits, which may check atmospheric elasticity.
This focused list is designed for practical use. Of the 45 planets, 27 transit in front of their stars, making them ideal for atmospheric analysis using transmission spectroscopy with the **James Webb Space Telescope (JWST)**. Other planets are suitable for direct imaging or light-curve studies with upcoming facilities such as the Extremely Large Telescope, the Nancy Grace Roman Space Telescope, and future missions such as the Habitable Worlds Observatory.
Kaltenegger stressed the strategic importance of the list, saying: “Our paper shows where we should look for life if we ever build a spacecraft like ‘Project Hail Mary’.” They said life may prove to be more diverse than currently imagined, even around flame-prone red dwarfs, which could challenge surface habitability.
This research offers a practical framework rather than speculation. Negative results from observations will also refine models of planetary atmospheres and habitability limits. As new data is received, some planets may drop from the priority list while others may gain priority. For the first time, the search for biosignals appears to be targeted and efficient, allowing the cosmic vast reservoir to be reduced to a manageable set of high-value targets.
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