Discovering an exoplanet isn’t what it used to be. Since the first detection of a planet around another star in 1995, astronomers have found thousands more, thanks in large part to the Kepler Space Telescope, which—truly an overachiever—has discovered nearly 5,000 potential worlds and verified about half of them. Even the discovery of the most exciting kind of exoplanet—an Earth-sized world orbiting inside a star’s habitable zone—has become routine: Kepler has confirmed the existence of more than 30 of them.
But that doesn’t mean the discoveries are boring.
A rocky planet similar in size and temperature to Earth is orbiting a nearby star called Ross 128, astronomers announced Wednesday. The star is a red dwarf, a type of star that is smaller and cooler than stars like our sun, located just 11 light-years from our solar system.
This makes the planet, which has been named Ross 128 b, the second-closest temperate, Earth-sized planet to our little corner of the universe. The closest is Proxima b, which resides four light-years away in the habitable zone of Proxima Centauri, our nearest star, and was discovered last year.
Ross 128 b was found by ESO’s High-Accuracy Radial-Velocity Planet Searcher (HARPS), an instrument located at the La Silla Observatory in Chile, and the discovery is described in a paper in Astronomy and Astrophysics. Astronomers at HARPS spent 10 years gathering and refining data, which included more than 160 measurements of Ross 128, before they found the signal that turned out to be an exoplanet, said Xavier Bonfils, the paper’s lead author, an astronomer at Institut de Planétologie et d’Astrophysique de Grenoble in France. “To detect such a small signal requires a lot of data,” Bonfils said.