TL;DR
GJ 887 d, confirmed in 2026, is the second closest potentially habitable planet to Earth at just 10.7 light-years away, orbiting a remarkably quiet red dwarf star. This makes it a far more favorable target for atmospheric study than the closer but violently flaring Proxima Centauri b.
What Happened
Astronomers have confirmed the existence of GJ 887 d, a rocky world orbiting within the habitable zone of the dim red dwarf GJ 887 (Lacaille 9352) only 10.7 light-years from Earth. The announcement, published by the European Southern Observatory (ESO), places the planet as the second nearest known potentially habitable exoplanet after Proxima Centauri b, but in a system whose star is far less hostile to life.
Key Facts
- GJ 887 d orbits a quiet red dwarf star (M0.5V) with low flaring activity, in stark contrast to Proxima Centauri, which bombards its planets with deadly stellar eruptions.
- The planet’s host star, GJ 887, lies just 10.7 light-years away in the southern constellation Piscis Austrinus – close enough to be seen with binoculars but too dim for the naked eye.
- GJ 887 d was confirmed in 2026 using over 15 years of radial velocity data from ESO’s HARPS and ESPRESSO spectrographs, which detected its gravitational pull on the star.
- The star has a mass of about 0.45 solar masses and a temperature of roughly 3,500 K; its habitable zone – where liquid water could exist – lies at an orbital distance of 0.1–0.2 astronomical units.
- Prior to this discovery, the GJ 887 system was already known to host two close-in super-Earths, GJ 887 b and c, discovered in 2020; GJ 887 d is the first temperate planet found in the system.
- GJ 887 d is likely a super-Earth or mini-Neptune with a mass between 3 and 8 Earth masses, though its exact radius remains unknown until atmospheric transit observations are attempted.
- The planet’s orbital period is expected to be between 30 and 100 days, placing it squarely in the star’s liquid-water zone while also allowing it to avoid tidal locking? (further studies needed).
Breaking It Down
The confirmation of GJ 887 d reshapes the hierarchy of nearby exoplanets. Proxima Centauri b remains the closest at 4.2 light-years, but its star is a volatile M dwarf that erupts with X-ray flares thousands of times stronger than the Sun’s. GJ 887 d, by contrast, orbits one of the most quiescent red dwarfs known. This stellar calm matters enormously: a quiet star preserves planetary atmospheres, reduces the probability of sterilizing radiation, and makes it far easier for astronomers to detect biosignature gases.
Proxima Centauri bombards its planet with X-ray flares that would strip a CO₂-rich atmosphere in under 100 million years; GJ 887’s star, by contrast, exhibits only one-tenth the flaring activity, giving GJ 887 d a realistic chance at retaining a thick, stable atmosphere.
That differential is the single most important analytical takeaway from this discovery. While Proxima b has captured headlines as Earth’s nearest neighbor, its actual habitability is deeply suspect. GJ 887 d, though farther away, offers a more promising environment for life as we know it. Astronomers can point telescopes at this system with far more confidence that any detected molecules – oxygen, methane, water vapor – would be signs of ongoing biospheres rather than transient artifacts of stellar activity.
The detection itself was a technical triumph. GJ 887 d’s radial velocity signal is extremely small – the star’s motion induced by the planet is only about 1 meter per second, buried in years of data. The confirmation required the combination of two ultra-precision spectrographs and a custom noise-modeling algorithm to disentangle the planet’s signal from the star’s own rotation and magnetic cycles. This level of measurement precision is now becoming routine, opening the door to detecting many more temperate worlds around nearby faint stars.
What Comes Next
The immediate priority is to determine whether GJ 887 d transits its host star – that is, passes across the face of the star as seen from Earth. If it does, astronomers could use the James Webb Space Telescope (JWST) to measure its atmosphere for the first time. A transit would also pin down the planet’s diameter, distinguishing a rocky super-Earth from a gaseous mini-Neptune.
- Transit search (2026–2027): Multiple observatories, including TESS and ground-based photometric surveys
