39 Eridani, an orange giant star in Eridanus
39 Eridani is an orange giant star in the constellation Eridanus. At 230 light years away, it shines at an apparent visual magnitude of 4.90.
39 Eridani (HIP 19777)
39 Eridani is an orange giant star in the constellation Eridanus. At 230 light years away, it shines at an apparent visual magnitude of 4.90. It is moving through the Galaxy at a speed of 54.7 km/s relative to the Sun.
Sky position: RA 4h 14.4m, Dec -10° 15.4'
Common designations: 39 Eridani, HR 1318, HD 26846, HIP 19777, Gaia DR3 3191969567826137600
39 Eridani has the spectral type K2III. 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 39 Eridani in the sky
39 Eridani lies in Eridanus. With a declination of -10° 15.4', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 80° 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 39 Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 63.59869958° (4h 14.4m) |
| Declination (J2000) | -10.25628346° (-10° 15.4') |
| Galactic Longitude | 203.57854713° |
| Galactic Latitude | -39.45104323° |
| Proper motion RA | -8.05 mas/yr |
| Proper motion Dec | -162.27 mas/yr |
| Parallax | 14.17 ± 0.10 mas |
| Spectral Type | K2III |
| Radial Velocity | 6.39 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 7.18 | 2.94 |
| B | 6.07 | 1.83 |
| V | 4.90 | 0.66 |
| R | 4.01 | -0.23 |
| I | 3.44 | -0.80 |
| J | 2.93 | -1.31 |
| H | 2.39 | -1.86 |
| K | 2.26 | -1.99 |
Colour index B-V: +1.17
Derivations
- Heliocentric distance: 70.57 pc (230 light years) (0.7% margin of error)
- Absolute visual magnitude: 0.66
- Transverse velocity: 54.4 km/s
- Space velocity relative to the Sun: 54.7 km/s
- Galactic position (X, Y, Z): -49.9 pc, -21.8 pc, -44.8 pc
- Galactic velocity (U, V, W): 30.0 km/s, -38.4 km/s, -24.8 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.