Akamar ( θ Eri / θ Eridanus / Theta Eridanus ) is a double star in the constellation of Eridanus .
| Theta Eridana | |||
|---|---|---|---|
| Star | |||
| Observational data ( Age J2000 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 120 St. years old | ||
| Visible magnitude ( V ) | 3.2 | ||
| Constellation | Eridan | ||
| Astrometry | |||
| Radial velocity ( R v ) | 11.9 km / s | ||
| Own movement (μ) | RA: −44.6 mas per year Dec: 19.0 mas per year | ||
| Parallax (π) | 28.00 ± 11.00 mas | ||
| Specifications | |||
| Spectral class | A4 III | ||
| Color Index ( B - V ) | 0.34 | ||
| Color Index ( U - B ) | 0.14 | ||
| |||
| Database Information | |||
| SIMBAD | data | ||
The name comes from the Arabic آخر النهر (ākhir an-nahr) - "end of the river" and is consonant with the name "Akhernar" of another star of the constellation - α Eridanus . In antiquity, θ Eridanus was the southernmost star of the constellation, rising above the horizon; thus, in Ptolemy, in the Almagest , she is described “as the last star of the River” (Eridanus). Subsequently, when, as a result of the precession, α Eridanus became available for observation, the name "Akhernar" began to be applied to it. Akamar can be observed under good observation conditions in southern Russia (starting at approximately 45 ° north latitude and south).
The main star, θ1 Erie, has a spectral class of A4 and has a visible magnitude of +3.2. His companion star, θ2 Erie, has a spectral class A1 and has a visible magnitude of +4.3. The angular separation of the two stars is 8.3 arc seconds. It is located at a distance of 120 light years from the Sun [2] .
Notes
- ↑ 1 2 3 4 A New Star Catalog of SAO Type - 1988.
- ↑ Perryman, MAC; Lindegren, L .; Kovalevsky, J. & et al. (1997), The Hipparcos Catalog, Astronomy and Astrophysics T. 323: L49 – L52