Nearby 25-light-year world now looks rocky after mass reestimate

Astronomers have revised the mass of the nearby exoplanet Gliese 3378 b down to about 2.3 Earth masses, shifting it from the edge of a mini-Neptune into the rocky regime. Its 21.45-day orbit places it in the star’s habitable zone at roughly 25 light-years away, making it a promising candidate for a rocky world; however, the existence of a solid surface or an atmosphere—and thus true habitability—still requires confirmation.