Epsilon Eridani b
Epsilon Eridani b, formally named AEgir, is a Jupiter-like exoplanet orbiting the nearby star Epsilon Eridani in the constellation Eridanus. It is about 10.5 light-years away. The planet was discovered in 2000 by a team led by Artie Hatzes using Doppler (radial-velocity) measurements, after earlier hints from other researchers.
The planet’s orbit around its star takes about 7.3 years, at a distance of roughly 3.5 astronomical units. The orbit is nearly circular (eccentricity around 0.06) and tilted about 40 degrees to our line of sight, roughly in line with the star’s outer dust disk. The true mass is close to Jupiter’s mass (about 0.8–1.0 Jupiter masses), with the radial-velocity data giving only a minimum mass of roughly 0.6–0.8 Mj depending on inclination.
IAU naming under NameExoWorlds gave AEgir to the planet (pronounced roughly “ee-jir”) and Ran to the star. The system also hosts debris material: a warm belt near 3 AU and an outer disk, which helps researchers study how the planet interacts with dust in the system.
Early on, the planet’s existence was debated due to stellar activity, but it is now treated as a confirmed planet. Attempts to image Epsilon Eridani b directly with the James Webb Space Telescope in 2024–2025 did not yield a statistically significant detection, though a faint signal was noted that could be noise.
Today, Epsilon Eridani b remains one of the closest Jupiter-like exoplanets, with ongoing observations aimed at pinning down its exact mass and orbit.
This page was last edited on 2 February 2026, at 02:56 (CET).