NASA has discovered a new exoplanet that could be a potential candidate for hosting life. The planet, named TOI-715 b, is a super-Earth, meaning it is larger than our planet but smaller than gas giants like Jupiter. It orbits a red dwarf star, a type of star smaller and cooler than the Sun, and is only 137 light-years away from us.
The discovery was made by NASA’s Transiting Exoplanet Survey Satellite (TESS), which launched in 2018 and has been adding to astronomers’ stockpile of habitable-zone exoplanets ever since. TESS detects planets by observing the tiny dips in brightness that occur when they cross the faces of their stars, as seen from Earth.
TOI-715 b is one and a half times as wide as Earth, and orbits within the “conservative” habitable zone around its parent star. That’s the distance from the star that could give the planet the right temperature for liquid water to form on its surface. Several other factors would have to line up, of course, for surface water to be present, especially having a suitable atmosphere. But the conservative habitable zone – a narrower and potentially more robust definition than the broader “optimistic” habitable zone – puts it in prime position, at least by the rough measurements made so far.
The planet has a “year” of only 19 days, meaning it completes one orbit around its star in that time. This is because red dwarfs are smaller and cooler than the Sun, so planets can crowd closer and still be safely within the star’s habitable zone. The tighter orbits also mean that these planets transit more often, making them easier to detect and observe.
The same system also might harbor a second, Earth-sized planet, which could also dwell just inside the conservative habitable zone. However, this planet is not yet confirmed and needs more observations to verify its existence.
TOI-715 b is a promising candidate for further investigation, as astronomers are beginning to write a whole new chapter in our understanding of exoplanets. The newest spaceborne instruments, including those onboard NASA’s James Webb Space Telescope, are designed not just to detect these distant worlds, but to reveal some of their characteristics. That includes the composition of their atmospheres, which could offer clues to the possible presence of life.
The discovery of TOI-715 b was announced in a paper published in The Astronomical Journal on January 31, 2024 .