Scientists have detected a super-Earth planet around a nearby red dwarf star, an important discovery as we continue to look for other habitable worlds.
The planet, GJ 625 b, is in orbit around an M dwarf star called GJ 625 about 21.2 light-years from us. It is thought to be at least 2.8 times the mass of Earth, and orbits its host in 14.6 Earth days. The findings, available on arXiv and led by the Canary Islands Institute of Astrophysics, will be published in the journal Astronomy and Astrophysics.
GJ 625 b is located on the inner edge of the habitable zone of the star, where temperatures are just right for liquid water to exist. It orbits at a distance of about 0.08 AU (astronomical unit, 1 AU is the distance from Earth to the Sun).
“GJ 625 b is a small super-Earth in the habitable zone of a nearby M-dwarf,” lead author Alejandro Suarez Mascareño, from the Canary Islands Institute of Astrophysics, told IFLScience. “Even after the last round of discoveries of small exoplanets around M-dwarfs, the number of rocky planets known around this kind of star is relatively small.”
This particular star is an M2 type of M dwarf, about a third the size and mass of our Sun. GJ 625 b is the lightest planet found around such a star.
Finding planets around M dwarfs is important, because it provides a “shortcut” to finding potentially habitable worlds. Planets around Sun-like stars are much more difficult to study, as they are in much wider orbits and their stars are much brighter.
Recently, worlds including Proxima b and LHS 1140 b have garnered a lot of interest, as they represent opportunities to study rocky exoplanets in more detail. But bigger (and rarer) planets like GJ 625 b present a better chance for study, being less drowned out by their host star in our observations.