Epsilon Eridani b

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**Epsilon Eridani b**
Discovery
Discovered by	Hatzes et al.
Discovery site	Tucson, Arizona, USA
Discovery date	August 7, 2000
Detection method	Radial velocity
Orbital characteristics
Periastron	1.01 AU
Apastron	5.77 AU
Semi-major axis	3.39 ± 0.36 AU
Eccentricity	0.702 ± 0.039
Orbital period	2502 ± 10 d
Average orbital speed	12.47 km/s
Inclination	30.1 ± 3.8°
Angular distance	1059.375 mas
Longitude of periastron	34°
Time of periastron	54207 ± 7 JD
Semi-amplitude	18.6 ± 2.9 m/s
Physical characteristics
Mass	1.55 ± 0.24 M_J

Epsilon Eridani b is an extrasolar planet around Epsilon Eridani, 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 3.3 AU from the star. The object's orbit is highly eccentric. Other observers, including Geoffrey Marcy required more information on the star's Doppler noise behaviour created by its large and varying magnetic field, and the discovery remained controversial until observations by the Hubble Space Telescope confirmed its existence^[1] The most favourable time for such an observation is estimated to be late December 2007. It's existence had also been previously suspected by a Canadian team led by Bruce Campbell and Gordon Walker in the early 1990s, but their observations weren't definitive enough to make a solid discovery.

The estimated mass is 1.5 times Jupiter's mass, and the orbit is inclined by an angle of 30° from our line of sight. This orbital inclination is parallel to the observed dust ring around the star. The planet is expected to reach periastron in 2007, when it could potentially be observed by the Hubble telescope.^[1]^[2]

[edit] References

^ ^a ^b "Hubble Zeroes in on Nearest Known Exoplanet", Hubble News Desk, 2006-10-09. Retrieved on 2006-10-10.
^ Benedict et al. (2006), The Extrasolar Planet ɛ Eridani b: Orbit and Mass, The Astronomical Journal, Volume 132, Issue 5, pp. 2206-2218; preprint