The planet and its host star are one of the planetary systems selected by the International Astronomical Union as part of their public process for giving proper names to exoplanets and their host star. The process involved public nomination and voting for the new names. In December 2015, the IAU announced the winning names were Ægir for the planet and Ran for the star. James Ott, age 14, submitted the names for the IAU contest and won.
Discovery
The planet's existence was suspected by a Canadian team led by Bruce Campbell and Gordon Walker in the early 1990s, but their observations were not definitive enough to make a solid discovery. Its formal discovery was announced on August 7, 2000 by a team led by Artie Hatzes. The discoverers gave its mass as 1.2 ± 0.33 times that of Jupiter, with a mean distance of 3.4 AU from the star. Observers, including Geoffrey Marcy, suggested that more information on the star's Doppler noise behaviour created by its large and varying magnetic field was needed before the planet could be confirmed. In 2006, the Hubble Space Telescope made Astrometric measurements and confirmed the existence of the planet. These observations indicated that the planet has a mass 1.5 times that of Jupiter and shares the same plane as the outer dust disk observed around the star. The derived orbit from these measurements is eccentric: either 0.25 or 0.7. Meanwhile, the Spitzer Space Telescope detected an asteroid belt at roughly 3 AU from the star. In 2009 Brogi's team claimed that the proposed planet's eccentricity and this belt were inconsistent: the planet would pass through the asteroid belt and rapidly clear it of material. The planet and the inner belt may be reconciled if that belt's material had migrated in from the outer comet belt. Astronomers are still collecting and analysing radial velocity data, while also trying to refine existing upper limits from direct imaging, on Epsilon Eridani b and this has led to a recently published paper, as of January 2019, claiming that the planet's orbital eccentricity is an order of magnitudesmaller than early estimates, at around 0.07, and consistent with a circular orbit, very similar to Jupiter's orbital eccentricity of 0.05. The updated measurements, amongst other things, also included new estimates for the mass and inclination of the planet, at 0.78 times the mass of Jupiter and an inclination of around 89 degrees. However, if the planet is later determined to be orbiting at the same inclination as the debris disc, that of 34 degrees, then its mass would be greater, at 1.19 times that of Jupiter.
