Australian astronomers have discovered a potentially habitable planet located about 150 light years from Earth.

The candidate planet, named HD 137010 b, was identified by an international research team led by University of Southern Queensland scientist Dr Alexander Venner, using data from NASA’s Kepler extended K2 mission collected in 2017.

The planet is estimated to be only around six per cent larger than Earth and is believed to have a surface temperature similar to Mars, potentially below minus 70 degrees Celsius. The findings were published in The Astrophysical Journal Letters.

Researchers found that HD 137010 b lies near the outer edge of its star’s habitable zone, where conditions could allow liquid water to exist on the planet’s surface. It was detected when it briefly passed in front of its host star during three months of Kepler observations, leaving only a very faint signal.

The initial clue was uncovered by a group of amateur citizen scientists, including Dr Venner, through the Planet Hunters project. Venner said his early involvement in the project while still in secondary school played a major role in inspiring his research career.

Co-author and University of Southern Queensland astrophysicist Dr Chelsea Huang said most previously identified potentially habitable planets orbit small, dim stars, where intense radiation can strip away planetary atmospheres. She noted that HD 137010 b is expected to have more favourable conditions for habitability.

Dr Venner added that HD 137010 b is the first Earth-sized planet candidate with Earth-like characteristics found transiting a Sun-like star bright enough for detailed follow-up studies. While current instruments cannot fully characterise the planet, he said future missions and advanced telescopes could make it a prime target in the search for Earth-like worlds.