Omega Eridani, a white subgiant star in Eridanus
Omega Eridani is a white subgiant star in the constellation Eridanus. At 218 light years away, it shines at an apparent visual magnitude of 4.40.
Omega Eridani (HIP 22701)
Omega Eridani is a white subgiant star in the constellation Eridanus. At 218 light years away, it shines at an apparent visual magnitude of 4.40. It is moving through the Galaxy at a speed of 11.2 km/s relative to the Sun.
Sky position: RA 4h 52.9m, Dec -5° 27.2'
Common designations: Omega Eridani, 61 Eridani, HR 1560, HD 31109, Gaia DR3 3188462022653817472, HIP 22701
Omega Eridani has the spectral type A9IVn. A-type stars are white stars with surface temperatures of roughly 7,500 to 10,000 K. Their spectra are dominated by strong hydrogen lines, and many of them rotate rapidly. Its luminosity class IV marks it as a subgiant: it has exhausted hydrogen in its core and is beginning to expand toward the giant phase.
How to find Omega Eridani in the sky
Omega Eridani lies in Eridanus. With a declination of -5° 27.2', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 85° N. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around December, which makes the weeks around that month the best time to observe it.
Tabulated data for Omega Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 73.22362244° (4h 52.9m) |
| Declination (J2000) | -5.45269632° (-5° 27.2') |
| Galactic Longitude | 203.74826480° |
| Galactic Latitude | -28.77848098° |
| Proper motion RA | -18.73 mas/yr |
| Proper motion Dec | 25.16 mas/yr |
| Parallax | 14.94 ± 0.12 mas |
| Spectral Type | A9IVn |
| Radial Velocity | 5.18 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 4.64 | 0.51 |
| V | 4.40 | 0.27 |
| J | 3.96 | -0.16 |
| H | 3.69 | -0.44 |
| K | 3.72 | -0.40 |
Colour index B-V: +0.24
Derivations
- Heliocentric distance: 66.96 pc (218 light years) (0.8% margin of error)
- Absolute visual magnitude: 0.27
- Transverse velocity: 10.0 km/s
- Space velocity relative to the Sun: 11.2 km/s
- Galactic position (X, Y, Z): -53.7 pc, -23.6 pc, -32.2 pc
- Galactic velocity (U, V, W): -7.5 km/s, 7.5 km/s, -3.8 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.