7 Eridani, a red giant star in Eridanus
7 Eridani is a red giant star in the constellation Eridanus. At 1,257 light years away, it shines at an apparent visual magnitude of 6.13.
7 Eridani (HIP 14040)
7 Eridani is a red giant star in the constellation Eridanus. At 1,257 light years away, it shines at an apparent visual magnitude of 6.13. It is moving through the Galaxy at a speed of 84.6 km/s relative to the Sun.
Sky position: RA 3h 0.8m, Dec -2° 52.7'
Common designations: 7 Eridani, CV Eridani, HR 904, HD 18760, HIP 14040, Gaia DR3 5186378382371856128
7 Eridani has the spectral type M0/1III. M-type stars are cool red stars below about 3,900 K whose spectra are dominated by titanium oxide molecular bands. Red dwarfs, red giants and red supergiants all fall in this class. Its luminosity class III marks it as a giant: an evolved star that has left the main sequence and swollen to many times its original size.
How to find 7 Eridani in the sky
7 Eridani lies in Eridanus. With a declination of -2° 52.7', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 87° N. It is just beyond naked-eye visibility; binoculars will show it easily. 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 7 Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 45.21200054° (3h 0.8m) |
| Declination (J2000) | -2.87862172° (-2° 52.7') |
| Galactic Longitude | 180.46721734° |
| Galactic Latitude | -50.69524367° |
| Proper motion RA | 8.32 mas/yr |
| Proper motion Dec | 8.25 mas/yr |
| Parallax | 2.59 ± 0.07 mas |
| Spectral Type | M0/1III |
| Radial Velocity | 81.84 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 7.88 | -0.05 |
| V | 6.13 | -1.80 |
| J | 2.73 | -5.20 |
| H | 1.87 | -6.06 |
| K | 1.62 | -6.31 |
Colour index B-V: +1.75
Derivations
- Heliocentric distance: 385.45 pc (1,257 light years) (2.6% margin of error)
- Absolute visual magnitude: -1.80
- Transverse velocity: 21.4 km/s
- Space velocity relative to the Sun: 84.6 km/s
- Galactic position (X, Y, Z): -244.2 pc, -2.0 pc, -298.3 pc
- Galactic velocity (U, V, W): -68.4 km/s, 0.8 km/s, -49.8 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.