A study posted in September 2026 calls Epsilon Eridani b the nearest Jupiter analogue known, a giant planet orbiting at roughly the distance of our own asteroid belt from the Sun. Its star is just 10.4 light-years away. The first strong claim for the planet came in 2000 from a team led by Artie Hatzes. They combined 20 years of radial velocity data, which track the tiny wobble a planet's gravity causes in its star, from four different telescopes.
The claim was hard to trust. Epsilon Eridani is magnetically active, and activity can mimic a planet's tug. Hatzes's team argued the star's activity cycles, at about 3 and 20 years, did not match the planet's signal. Doubts lingered until 2019, when a team led by Dimitri Mawet confirmed the planet using 30 years of radial velocity data. They found about 0.78 times Jupiter's mass and a 7.4-year orbit 3.5 AU from the star, where 1 AU is the Earth–Sun distance. The orbit is nearly circular, ten times less stretched than the first estimate suggested.
No one has yet photographed it. Mawet's team searched with an infrared camera and a coronagraph, a device that blocks a star's glare, on the Keck telescope and found nothing. A 2025 search with the James Webb Space Telescope's NIRCam coronagraph also found no significant signal, though it ruled out Saturn-mass planets beyond about 16 AU. That search also looked for a second planet that may shape the star's outer ring of dust.
Because the planet has only been sensed through its pull, its size, temperature and atmosphere have not been measured. Mass estimates also vary: the 2026 study, combining radial velocities, precise star positions and Webb's limits, finds 0.91 Jupiter masses. It predicts that the coronagraph on NASA's upcoming Roman Space Telescope should see the planet in reflected light if it has clouds.
TerraForge's model, working only from its mass, orbit and star, classifies Epsilon Eridani b as a gas giant, which agrees with its measured mass. Its modelled 117 K is close to the archive's 112 K equilibrium temperature, but no direct measurement exists yet to test either figure.