Astronomers at the University of California, Irvine have discovered a super-Earth exoplanet, GJ 251 c, orbiting an M-dwarf star just 18 light-years from Earth. This rocky world lies in the star's habitable zone, where conditions might allow liquid water essential for life. The find positions it as a prime target for future direct imaging with advanced telescopes.
The discovery of GJ 251 c highlights progress in exoplanet detection amid challenges posed by active stars. Researchers used high-precision instruments, including the Habitable-zone Planet Finder (HPF) and NEID, to measure subtle radial velocity shifts in the star's light caused by the planet's gravitational pull. These tools, developed with input from UC Irvine's Paul Robertson, operate effectively in the infrared to minimize interference from the M-dwarf's starspots and flares.
Published in The Astronomical Journal, the study by lead author Corey Beard and collaborators confirms GJ 251 c as a super-Earth—several times Earth's mass—with a potentially rocky composition. "We have found so many exoplanets at this point that discovering a new one is not such a big deal," Robertson noted. "What makes this especially valuable is that its host star is close by, at just about 18 light-years away. Cosmically speaking, it's practically next door."
The planet's proximity makes it accessible for direct observation using the upcoming Thirty Meter Telescope (TMT), under development by the University of California. Beard emphasized its potential: "TMT will be the only telescope with sufficient resolution to image exoplanets like this one. It's just not possible with smaller telescopes."
While statistical models support the planet's existence, the team calls for community efforts and further observations as TMT nears operation. Collaborators include experts from UCLA, Pennsylvania State University, and the University of Colorado, Boulder. Funding came from NSF grant AST-2108493, NASA/NSF's NN-EXPLORE program (grant 1716038), and NASA's ICAR program (80NSSC23K1399). This candidate could yield insights into habitable worlds beyond our solar system.