“Project Hail Mary” – These 45 Exoplanets Could Be Home to Alien Life, Scientists Say

A small group of distant worlds may hold the clues to life beyond Earth.

Astronomers searching for life beyond Earth have narrowed down the most promising places to look.

Out of more than 6,000 known exoplanets, researchers have identified just under 50 rocky worlds that are most likely to support life.

The findings, published in Monthly Notices of the Royal Astronomical Society, echo the premise of the recent film Project Hail Mary, where Ryan Gosling’s character travels to another star system in a desperate attempt to save Earth. Along the way, he encounters an alien named Rocky and fictional microorganisms called Astrophage and Taumoeba.

Professor Lisa Kaltenegger, director of the Carl Sagan Institute at Cornell University, led the study with a team of undergraduate students. Using data from the European Space Agency’s Gaia mission and NASA’s Exoplanet Archive, they identified planets located in the so called habitable zone.

This region sits at just the right distance from a star. It is not so close that temperatures become extreme, and not so far that conditions are frozen. Planets in this zone are more likely to have liquid water on their surfaces, a key ingredient for life.

The study also highlights planets that receive levels of stellar energy similar to what Earth gets from the Sun.

A Search Inspired by Science and Fiction

“As Project Hail Mary so beautifully illustrates, life might be much more versatile than we currently imagine, so figuring out which of the 6,000 known exoplanets would be most likely to host extraterrestrials such as Astrophage and Taumoeba – or Rocky – could prove critical, and not just to Ryan Gosling,” Professor Kaltenegger said.

“Our paper reveals where you should travel to find life if we ever built a ‘Hail Mary’ spacecraft.”

The team identified 45 rocky planets within the habitable zone that could potentially support life. They also selected 24 additional candidates within a more restrictive three-dimensional habitable zone, which assumes tighter limits on how much heat a planet can tolerate.

The list includes well-known worlds such as Proxima Centauri b, TRAPPIST-1f, and Kepler 186f, along with less familiar targets like TOI-715 b.

Among the most compelling targets are TRAPPIST-1 d, e, f, and g, which lie about 40 light-years from Earth, and LHS 1140 b, about 48 light-years away. These worlds stand out not because anyone knows they are inhabited, but because they combine the kinds of traits astronomers care about most: rocky composition, potentially mild temperatures, and a chance of holding onto an atmosphere. Without an atmosphere, even a planet in the habitable zone may be barren.

The study also points to planets that get nearly Earth-like levels of radiation from their stars. Those include the transiting planets TRAPPIST-1 e, TOI-715 b, Kepler-1652 b, Kepler-442 b, and Kepler-1544 b. Others, including Proxima Centauri b, GJ 1061 d, GJ 1002 b, and Wolf 1069 b, were found through the subtle wobble they induce in their host stars.

That mix is important. Transiting planets pass in front of their stars from our point of view, allowing telescopes to sample starlight filtering through any atmosphere they may have. Wobble-detected planets are harder to study that way, but they still help scientists map out which nearby rocky worlds deserve closer attention.

Testing the Limits of Habitability

The researchers also focused on planets near the inner and outer edges of the habitable zone to better understand where habitability begins and ends. Although the concept has been studied since the 1970s, new observations are needed to confirm or refine existing models, Kaltenegger said.

Planets with highly elliptical orbits may also provide insights. These worlds experience changing levels of heat as they move closer to and farther from their stars, offering clues about whether a planet must remain in the habitable zone at all times to support life.

Inner edge candidates include K2-239 d, TOI-700e, and K2-3d, along with Wolf 1061c and GJ 1061c, which are identified through stellar wobble. TRAPPIST-1g, Kepler-441b, and GJ 102 could help researchers study the colder outer boundary of the habitable zone.

“While it’s hard to say what makes something more likely to have life, identifying where to look is the first key step – so the goal of our project was to say ‘here are the best targets for observation’,” said Gillis Lowry, now a graduate student at San Francisco State University.

Fellow researcher Lucas Lawrence, now a graduate student at the University of Padua in Italy, said: “We wanted to create something that will enable other scientists to search effectively and we kept discovering new things about these worlds we wanted to investigate further.”

Learning from Our Solar System

Co-author Abigail Bohl of Cornell University explained that our own Solar System provides a useful benchmark.

“We know Earth is habitable, while Venus and Mars are not. We can use our Solar System as a reference to search for exoplanets that receive stellar energy between what Venus and Mars get.”

“Observing these planets can help us understand when habitability is lost, how much energy is too much, and which planets remain habitable – or maybe never were.”

“The same idea applies to eccentric planets: how much orbital eccentricity can a planet have while still holding onto its surface water and habitable conditions?”

“We identified planets at the inner and outer edges of the habitable zone, as well as those with the highest eccentricities, to test our understanding of what it takes for a planet to be and remain habitable. We also identified the targets that are most observable with the James Webb Space Telescope (JWST) and other telescopes.”

Guiding Future Observations

The researchers also highlighted the best targets for different observation methods, increasing the chances of detecting signs of life if they exist.

Their catalog will help guide observations with current and future telescopes, including the James Webb Space Telescope, the Nancy Grace Roman Space Telescope scheduled for launch in 2027, the Extremely Large Telescope expected to see first light in 2029, the Habitable Worlds Observatory planned for the 2040s, and the proposed Large Interferometer For Exoplanets project.

According to Lowry, studying these small exoplanets is the only way to determine whether they have atmospheres and to refine our understanding of the habitable zone.

She added that the team has already begun examining 10 planets with Earth-like radiation levels. Two of them, TRAPPIST-1 e and TOI-715 b, are close enough for detailed study with current or upcoming telescopes.

The TRAPPIST-1 system is already a major focus for observations with the James Webb Space Telescope, led by Cornell astronomer Nikole Lewis. Both TRAPPIST-1 and TOI-715 are small red stars, which makes it easier to detect and study the Earth-sized planets orbiting them.

Reference: “Probing the limits of habitability: a catalogue of rocky exoplanets in the habitable zone” by Abigail Bohl, Lucas Lawrence, Gillis Lowry and Lisa Kaltenegger, 19 March 2026, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stag028

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