Astronomers have identified a planet candidate, HD 137010 b, that shares striking similarities with Earth in size and orbital period, but with a potentially frigid twist. The exoplanet, located approximately 146 light-years away, could be significantly colder than Mars, raising intriguing questions about the diversity of worlds beyond our solar system and the potential for habitability in unexpected places. The discovery, made through re-analysis of data from NASA’s retired Kepler Space Telescope, was detailed in a paper published January 27, 2026, in The Astrophysical Journal Letters.
While HD 137010 b is roughly 6% larger than Earth and completes an orbit in about 355 days – remarkably close to Earth’s year – its host star is cooler and dimmer than our Sun. This means the planet receives only about one-third the heat that Earth does, placing it near the outer edge of its star’s habitable zone. The potential for liquid water on the surface, a key ingredient for life as we know it, hinges on the presence of a substantial atmosphere, a factor currently unknown.
The research team, led by Alexander Venner, a postdoctoral researcher at the Max Planck Institute for Astronomy who was a doctoral student at the University of Southern Queensland at the time of the discovery, utilized the transit method to detect the planet. This technique involves observing the slight dimming of a star’s light as a planet passes in front of it. The signal from HD 137010 b was initially flagged by citizen scientists participating in the Planet Hunters project, highlighting the power of collaborative science.
Artist’s concept of exoplanet candidate HD 137010 b, dubbed a “cold Earth” because it’s a possible rocky planet slightly larger than Earth, orbiting a Sun-like star about 146 light-years away. (NASA/JPL-Caltech/Keith Miller)
A Chilling Prospect: Temperature and Composition
Current estimates suggest HD 137010 b’s equilibrium temperature could be as low as -68°C (-90°F), potentially colder than the average surface temperature of Mars, which hovers around -65°C (-85°F) [NASA]. Yet, scientists caution that this is just an estimated temperature, and the actual surface temperature could vary significantly depending on the planet’s atmosphere. A thick atmosphere could trap heat and raise the temperature, while a thin or absent atmosphere would result in even colder conditions. The planet is classified as a potential Super-Earth or Earth analog, suggesting a rocky composition, but further observations are needed to confirm this.
Challenges in Confirmation and Future Observations
HD 137010 b remains a “candidate” planet, meaning its existence hasn’t been definitively confirmed. The signal was detected from a single transit event during the Kepler mission’s K2 campaign in 2017, making further observations crucial. The planet’s long orbital period means that transit events are rare, posing a significant challenge for astronomers. [Wikipedia] states that confirmation requires additional transits or alternative observations.
Future missions, such as NASA’s Transiting Exoplanet Survey Satellite (TESS) and the European Space Agency’s CHaracterising ExOPlanet Satellite (CHEOPS), are well-positioned to conduct follow-up observations. These telescopes are designed to detect and characterize exoplanets with greater precision, potentially providing the data needed to confirm HD 137010 b’s existence and determine its atmospheric composition.
Implications for the Search for Habitable Worlds
The discovery of HD 137010 b highlights the diverse range of exoplanets that exist and challenges our assumptions about what makes a planet habitable. Even if this particular world proves to be too cold to support life as we know it, it demonstrates that Earth-sized planets can exist in a variety of environments. [ScienceDaily] reports that the planet’s existence offers new hope in the search for worlds with atmospheres and the potential for water beyond our galaxy.
The ongoing analysis of data from retired missions like Kepler continues to yield valuable insights into the exoplanet population. As technology advances and new missions are launched, our understanding of these distant worlds will undoubtedly deepen, bringing us closer to answering the fundamental question of whether we are alone in the universe.
This research underscores the importance of continued exploration and the potential for surprising discoveries in the vast expanse of space. Share your thoughts on this intriguing exoplanet candidate in the comments below.
Disclaimer: This article provides information for general knowledge and informational purposes only, and does not constitute medical or scientific advice.