A team of astronomers has confirmed that the nearby star GJ 887 hosts not three but at least four planets — and one of them is a super-Earth sitting squarely in the habitable zone, making it only the second known potentially habitable world within 10 light-years of Earth.
Located just 10.7 light-years away in the constellation Tucana, GJ 887 (also known as Gliese 887) is one of the brightest red dwarf stars in the sky. Its proximity and brightness make it an exceptional laboratory for exoplanet science.
The star was already known to host two super-Earths — GJ 887 b and c — discovered in 2020 with the HARPS spectrograph. A third signal, appearing every 50 days, was tentatively noted but could not be distinguished from stellar magnetic activity at the time.
To settle the question, the research team gathered 101 new HARPS observations and 12 measurements from ESPRESSO, a more precise spectrograph on the Very Large Telescope in Chile. Crucially, during the new observing campaign, the star's magnetic activity increased, revealing a rotation period of about 39 days. This allowed the team to build a sophisticated model separating stellar noise from true planetary signals.
The result: GJ 887 d is confirmed — a super-Earth with a minimum mass of about six Earth masses, orbiting every 51 days within the habitable zone. The habitable zone is the distance from a star where temperatures could allow liquid water to exist on a planet's surface, a key ingredient for life as we know it.
The team also discovered a previously hidden fourth planet, GJ 887 e — an Earth-mass world orbiting too close to its star (every 4.4 days) to be habitable. A probable fifth planet, GJ 887 f, was also detected but requires further observations for confirmation.
GJ 887 d now meets the criteria for inclusion in the Habitable Worlds Catalog at the University of Puerto Rico at Arecibo, joining only 70 other exoplanets out of over 5,000 known. It is second only to Proxima Centauri b in proximity among confirmed habitable zone planets.
What makes this discovery especially significant is the potential for atmospheric characterization. Future observatories like NASA's Habitable Worlds Observatory (HWO, projected for the 2040s) and the Large Interferometer For Exoplanets (LIFE) will be designed to directly image nearby exoplanets and analyze their atmospheres for biosignature gases.
"GJ 887 d's proximity to Earth makes it a prime candidate for the next generation of space observatories," the researchers write in their paper, accepted for publication in Astronomy & Astrophysics. At just 10.7 light-years away, it offers our best near-term chance to study the atmosphere of a potentially habitable world — and perhaps find the first signs of life beyond our solar system.
