25 Eridani, an orange giant star in Eridanus
25 Eridani is an orange giant star in the constellation Eridanus. At 408 light years away, it shines at an apparent visual magnitude of 5.55.
25 Eridani (HIP 17506)
25 Eridani is an orange giant star in the constellation Eridanus. At 408 light years away, it shines at an apparent visual magnitude of 5.55. It is moving through the Galaxy at a speed of 74.8 km/s relative to the Sun.
Sky position: RA 3h 44.9m, Dec -0° 17.8'
Common designations: 25 Eridani, HR 1150, HD 23413, HIP 17506, Gaia DR3 3251584263648218624
25 Eridani has the spectral type K3III. K-type stars are orange stars with surface temperatures of about 3,900 to 5,300 K. Their spectra are rich in neutral metal lines and, in the cooler examples, molecular bands. 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 25 Eridani in the sky
25 Eridani lies in Eridanus. With a declination of -0° 17.8', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 90° 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 25 Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 56.23540520° (3h 44.9m) |
| Declination (J2000) | -0.29672064° (-0° 17.8') |
| Galactic Longitude | 187.48288416° |
| Galactic Latitude | -40.48525919° |
| Proper motion RA | 58.85 mas/yr |
| Proper motion Dec | -1.98 mas/yr |
| Parallax | 7.99 ± 0.06 mas |
| Spectral Type | K3III |
| Radial Velocity | 66.12 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 6.97 | 1.49 |
| V | 5.55 | 0.06 |
| J | 3.36 | -2.13 |
| H | 2.60 | -2.89 |
| K | 2.40 | -3.09 |
Colour index B-V: +1.42
Derivations
- Heliocentric distance: 125.21 pc (408 light years) (0.7% margin of error)
- Absolute visual magnitude: 0.06
- Transverse velocity: 35.0 km/s
- Space velocity relative to the Sun: 74.8 km/s
- Galactic position (X, Y, Z): -94.4 pc, -12.4 pc, -81.3 pc
- Galactic velocity (U, V, W): -64.7 km/s, -30.4 km/s, -22.1 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.