Omicron (2) Eridani
| Omicron Eridani | |
| Stellar characteristics | |
|---|---|
| Constellation | Eridanus |
| Right ascension (Epoch J2000) | 04h 15m 16.32s |
| Declination (Epoch J2000) | -07° 39' 10.34" |
| Distance from Sol | 16.5 ly |
| Other designations | Keid, 40 Eridani |
Also known as Keid, this triple star system is located less than 16.5 light-years (ly) away in the northernmost part (04:15:16.32-07:39:10.34, ICRS 2000.0) of Constellation Eridanus, the River -- northeast of Zaurak, Gamma Eridani. It is visible in the night sky. Because Omicron1 Eridani was named "The Egg" (Al Baid, now Beid) by the Arabs for its position near the nest of the Ostrich (Theta Eridani 2, which is located much further south), Omicron2 Eridani nearby to the southeast was called "The Egg-shells" (or Al Kaid, now "Keid").
40 Eridani A
40 Eridani A is a main sequence, orange-red dwarf (K1 Ve) may have about 89 percent of Sol's mass (RECONS), about 85 percent of its diameter (Johnson and Wright, 1983, page 655), and 36 percent of its luminosity. The star appears to be 46 percent to 102 percent as enriched as Sol with elements heavier than hydrogen ("metallicity"), based on its abundance of iron (Cayrel de Strobel et al, 1991, page 282). The system shows a radial velocity of about 25 miles per second (mps) -- about 40 km per second or kps -- in recession, but the true space velocity is about 62 mps (or 100 kps). Star A and the binary pair BC have a wide separation of about 418 AUs and an orbital period of some 8,000 years (Wulff Dieter Heintz, 1974). Some alternative useful star catalogue numbers for the star are: Omi2 Eri A, 40 Eri A, HR 1325, Gl 166 A, Hip 19849, HD 26965, BD-07 780, SAO 131063, LHS 23, and LTT 1907.
40 Eridani B
A white dwarf (DA4 /VII). It has a mass estimated from about 50.1 percent of Sol's (Provencal et al, 1998), only two percent of its diameter, and 33/10,000th of its brightness. The B and C pair of stars have an "average" separation of about 35 AUs (of a semi-major axis) in a highly elliptical orbit (e= 0.410) that lasts about 252 years and swings between 21 and 49 AUs (Heintz, 1974). (See an animation of the orbits of Stars A, B, and C and their potentially habitable zones, with a table of basic orbital and physical characteristics.) Some alternative useful star catalogue numbers for the star are: Omi2 Eri B, 40 Eri B, Gl 166 B, HD 26976, BD-07 781, G 160-60, LHS 24, ADS 3093, W 33, and Struve 518.
40 Eridani C
A very dim red dwarf (M4.5 Ve) with only about 19.5 percent of Sol's mass (RECONS), 28 percent of its diameter (Johnson and Wright, 1983, page 655), and 7/10,000th of its luminosity. Star C is also a UV Ceti type, flare star, which has the variable star designation of DY Eridani. Some alternative useful star catalogue numbers for the star are: DY Eri, Omi2 C, 40 Eri C, Gl 166 C, LTT 1909, and LHS 25.
(Boilerplate from SolStation.com)
