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Astronomers have discovered a candidate exoplanet, HD 137010b, that may orbit in the outer reaches of its star’s habitable zone, 146 light-years from Earth. While its existence is not yet fully confirmed, early observations suggest it could be a rocky world with conditions that might support life—if it has a substantial atmosphere.

What We Know About HD 137010b

HD 137010b orbits a K-type dwarf star, which is slightly smaller, cooler, and dimmer than our Sun. The planet receives only about 29% of the light and heat that Earth gets, placing it at the very edge of its star’s habitable zone. Estimates suggest HD 137010b is just 1.06 times the diameter of Earth and completes one orbit roughly every 355 days, similar to an Earth year.

Without an atmosphere, the planet’s surface could average –90°F (–68°C), slightly colder than Mars. However, a thicker atmosphere—especially one rich in greenhouse gases like carbon dioxide—could trap heat and allow liquid water to exist on its surface.

How HD 137010b Was Detected

The candidate planet was identified by astronomers led by Alexander Venner at the Max Planck Institute for Astronomy in Germany. They analyzed archival data from NASA’s Kepler Space Telescope K2 mission. Only a single transit—a brief dimming of the host star as the planet passed in front—was observed. Normally, confirming a planet requires at least two or three transits, so additional observations are necessary.

Venner’s team was able to rule out false positives, such as stellar activity or background stars, by comparing historical images and using data from other telescopes.

Future Observations and Atmosphere Search

HD 137010b’s host star is relatively bright (magnitude 10), making it accessible for both professional observatories and advanced amateur telescopes. Detecting the planet’s atmosphere would involve measuring starlight filtered through the planet during transit and subtracting the star’s light when the planet is hidden behind it.

NASA’s TESS, ESA’s CHEOPS, and the upcoming PLATO mission, scheduled for launch in December 2026, could provide the next opportunity to observe transits and gather data on the planet’s size, orbit, and possible atmosphere.

Could HD 137010b Support Life?

Researchers estimate a 40% chance that HD 137010b is within the “conservative” habitable zone, where conditions are more restrictive for liquid water. There is a 51% chance it lies in the broader “optimistic” habitable zone, where rotational effects and geothermal heat could keep the planet warmer. Even so, there remains a significant possibility—around 50%—that the planet is outside the habitable zone entirely.

While the surface may be frozen without an atmosphere, a CO₂-rich atmosphere or other greenhouse gases could allow for liquid water and moderate temperatures. Scientists emphasize that more data is needed before determining the planet’s true potential for habitability.