Iota Eridani, an orange giant star in Eridanus
Iota Eridani is an orange giant star in the constellation Eridanus. At 146 light years away, it shines at an apparent visual magnitude of 4.12.
Iota Eridani (HIP 12486)
Iota Eridani is an orange giant star in the constellation Eridanus. At 146 light years away, it shines at an apparent visual magnitude of 4.12. It is moving through the Galaxy at a speed of 30.5 km/s relative to the Sun.
Sky position: RA 2h 40.7m, Dec -39° 51.3'
Common designations: Iota Eridani, HR 794, HD 16815, Gaia DR3 4951967794731342464, HIP 12486
Iota Eridani has the spectral type K0IIIb. 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 Iota Eridani in the sky
Iota Eridani lies in Eridanus. With a declination of -39° 51.3', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 50° N. Observers poleward of latitude 50° S see it as circumpolar: it never sets. It is bright enough to see with the naked eye under dark skies. It is highest in the sky at local midnight around November, which makes the weeks around that month the best time to observe it.
Tabulated data for Iota Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 40.16681187° (2h 40.7m) |
| Declination (J2000) | -39.85537653° (-39° 51.3') |
| Galactic Longitude | 249.29718155° |
| Galactic Latitude | -64.06518195° |
| Proper motion RA | 135.60 mas/yr |
| Proper motion Dec | -27.23 mas/yr |
| Parallax | 22.29 ± 0.11 mas |
| Spectral Type | K0IIIb |
| Radial Velocity | -8.13 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 5.11 | 1.85 |
| V | 4.12 | 0.86 |
| J | 2.10 | -1.16 |
| H | 1.56 | -1.70 |
| K | 1.51 | -1.75 |
Colour index B-V: +1.00
Derivations
- Heliocentric distance: 44.87 pc (146 light years) (0.5% margin of error)
- Absolute visual magnitude: 0.86
- Transverse velocity: 29.4 km/s
- Space velocity relative to the Sun: 30.5 km/s
- Galactic position (X, Y, Z): -6.9 pc, -18.4 pc, -40.4 pc
- Galactic velocity (U, V, W): -12.6 km/s, -19.3 km/s, 20.0 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.