Astronomers have discovered a potentially habitable planet 146 light-years away that is similar in size to Earth but may experience extreme cold, with surface temperatures possibly as low as -70°C.
Named HD 137010 b, the planet orbits a sun-like star and is thought to have a roughly 50% chance of residing in its star’s habitable zone, the region where conditions could allow liquid water to exist.
The discovery was announced by an international team of scientists from Australia, the UK, the US, and Denmark, using data from NASA’s Kepler space telescope’s extended K2 mission collected in 2017.
Dr Chelsea Huang, a researcher at the University of Southern Queensland (USQ) in Australia and co-author of the study, said the planet’s orbit, approximately 355 days, is “very similar to Earth’s orbit around the Sun.”
“What’s very exciting about this particular Earth-sized planet is that its star is only about 150 light-years away from our solar system,” Huang said. “The next best planet around a sun-like star in a habitable zone is about four times farther and 20 times fainter, making HD 137010 b uniquely close in astronomical terms.”
The planet was initially detected when it briefly crossed in front of its star, causing a tiny dip in brightness. This faint signal was first noticed by citizen scientists participating in the Planet Hunters project, including Dr Alexander Venner, the study’s lead author, who spotted it while he was still a high school student.
“I contributed to this citizen science project back in secondary school, and it played a huge part in getting me into research,” Venner said. “Returning to this work and uncovering such an important discovery has been an incredible experience.”
Dr Huang said the team’s first reaction to the discovery was disbelief. “Our immediate thought was that this cannot possibly be true. But after double- and triple-checking the data, it became clear this is a textbook example of a planetary transit.”
Because HD 137010 b orbits a star cooler and dimmer than the Sun, its surface temperature may be far below that of Earth, potentially resembling the cold climate of Mars.
This has led some experts to suggest the planet could be a “super snowball,” a largely icy world with frozen water rather than a temperate, Earth-like environment.
Dr Sara Webb, an astrophysicist at Swinburne University not involved in the study, noted: “The discovery is very exciting, but only one transit has been detected. In planetary science, we typically look for at least three to confirm a planet. While it is Earth-sized, it may be icy rather than habitable in the traditional sense.”
Despite the frigid temperatures, the proximity of HD 137010 b makes it an ideal target for observation with next-generation telescopes.
Dr Huang said, “The brightness and closeness of this star put it well within reach of upcoming observational technology. I expect it to be among the first targets for detailed study as new instruments come online.”
HD 137010 b’s discovery highlights the growing importance of citizen science in modern astronomy. Venner’s involvement demonstrates how projects like Planet Hunters can help identify promising exoplanet candidates that professional astronomers might otherwise overlook.
“Being able to make a contribution from my own bedroom as a student and then later join the research team has been an extraordinary journey,” Venner said. “It underscores how collaborative science has become.”
The research, published in Astrophysical Journal Letters, adds to a growing list of potentially habitable exoplanets orbiting stars similar to the Sun.
While planets such as Kepler-186f and Proxima Centauri b have attracted attention in the past, HD 137010 b is remarkable because of its relative closeness to Earth and its Earth-like orbit.
Huang emphasized, “In terms of studying planets around Sun-like stars, this discovery is a step change. It allows us to probe questions about habitability in a much more tangible way than ever before.”
Though currently unreachable with present-day technology, HD 137010 b sparks imagination about the future of space exploration.
Webb cautioned, “Even at the speed of current spacecraft, traveling there would take tens of thousands, if not hundreds of thousands, of years. But in terms of scientific study, we can still learn a tremendous amount from observation and modeling.”
The team is now planning follow-up studies using both ground-based observatories and upcoming space telescopes to confirm HD 137010 b’s status and gather more information about its atmosphere, composition, and potential for hosting life.
Dr Huang added: “This planet is going to be a primary target for the next generation of telescopes. We want to understand not just its orbit, but whether it has an atmosphere, water, or other indicators that could point toward habitability.”
Dr Venner also highlighted the broader implications for planetary science: “Discoveries like this show how little we still know about the diversity of planetary systems in our galaxy. Each new planet provides a data point that can refine our understanding of how Earth-like planets form and survive.”
The announcement of HD 137010 b is part of a wider surge in exoplanet research. Missions such as Kepler, TESS, and future telescopes like the James Webb Space Telescope have revolutionized astronomers’ ability to detect planets beyond the solar system.
According to Huang, “The pace of discovery is accelerating, and with HD 137010 b we have a chance to study an Earth-sized planet that is both close and accessible to observation. It’s incredibly exciting for the field.”
While the cold climate may preclude traditional forms of life as we know it, HD 137010 b represents a valuable opportunity to test models of planetary habitability and climate.
Webb said: “Even if it’s mostly frozen, understanding such planets gives insight into the variety of conditions in which planets can exist, and how they might evolve over billions of years.”
In conclusion, the discovery of HD 137010 b, a potentially habitable planet 146 light-years away, marks a significant milestone in the search for Earth-like worlds.
Its proximity, Earth-like size, and orbit around a Sun-like star make it an unprecedented candidate for future study. Scientists around the world are eager to explore its atmosphere, potential water content, and surface conditions, which could yield insights into the prevalence of habitable planets in our galaxy.
As Dr Huang said, “It’s rare to find a planet that is Earth-sized, close, and in a potentially habitable zone around a Sun-like star. HD 137010 b is the perfect target for advancing our understanding of exoplanets and, eventually, the possibilities for life beyond Earth.”
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