In 2020, a study confirmed that two planets orbited the nearby red dwarf, GJ 887. Now, astronomers have confirmed the existence of two additional planets orbiting GJ 887 in a new study published in Astronomy and Astrophysics. The new study suggests that one of these newly confirmed planets is in the habitable zone.
The GJ 887 red dwarf system
GJ 887 is a bright red dwarf star about 10.7 light years away from our solar system—a relatively short distance compared to other star systems. The previous study showed two non-transiting exoplanets with short orbital periods of 9 and 21 days and a potential third planet with a period of 50 days. At the time, available data could not differentiate whether the signal that was interpreted as potentially being from the third planet was coming from a planet or magnetic activity from the star.
Red dwarf stars are prime targets for finding low-mass planets in the habitable zone (HZ)—a region within a particular distance from a star where a planet’s surface temperature allows for the existence of liquid water. The team involved in the new study aimed to determine whether this potential third planet could be confirmed and whether there might be any additional planets.
“The combination of the quiet, nearby star, confirmed planets close to the inner edge of the HZ, and the possibility of a third planet within the HZ means GJ 887 is particularly interesting for further characterization. If the 50 d signal is due to a planet, the system would be a prime candidate for atmospheric characterization, with such proposed imaging missions such as the Habitable Worlds Observatory (HWO) or interferometry missions such as Large Interferometer For Exoplanets (LIFE) due to its brightness and proximity to the sun,” the study authors write.
New data confirms additional planets
The researchers combined new radial velocity (RV) measurements from the new High Accuracy Radial velocity Planet Searcher (HARPS) and Echelle SPectrograph for Rocky Exoplanets and Stable Spectroscopic Observations (ESPRESSO) spectral data and archival data. They also used photometric data from the Transiting Exoplanet Survey Satellite (TESS) and All-Sky Automated Survey (ASAS) to determine transits and stellar rotation.
The results confirmed that four planets orbit GJ 887 with periods of 4.4, 9.2, 21.8, and 50.8 days. They also confirmed that the 50.8-day planet (GJ 887 d) is in the HZ, making it the second closest HZ planet after Proxima Centauri b. The team says that the planet appears to be a “super-Earth” with a minimum mass of over six Earth masses.
“Without an independent radius estimate, the density and hence the composition of the planet cannot be determined. According to Luque and Pallé, planets in this mass range have either a rocky, a water-world or a puffy sub-Neptune composition,” the study authors explain.
A fifth signal at 2.2 days was detected in the study, but could not be confirmed. The team says that, if confirmed, this may be a sub-Earth-mass planet. Future studies may confirm the existence of this potential planet with additional high-precision radial velocity data.
An ideal target for future study
The GJ 887 system is likely to remain in the crosshairs of astronomical instruments for years to come. GJ 887 d is a prime target for future direct imaging missions studying atmospheres and searching for biosignatures, such as the HWO and LIFE missions. There will likely be continued interest in determining the composition of GJ 887 d to see if it can support life.
“GJ 887 is a compelling system for further study. It is a nearby and, hence, bright, M dwarf, hosting a minimum of four planets, including a super-Earth-mass, Earth-mass, and potentially sub-Earth-mass planets. At least one of the planets is in the habitable zone,” the study authors write. https://phys.org/news/2026-03-nearby-red-dwarf-star-hosts.html
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