Tau-3 Eridani, a white subgiant star in Eridanus
Tau-3 Eridani is a white subgiant star in the constellation Eridanus. At 88 light years away, it shines at an apparent visual magnitude of 4.09.
Tau-3 Eridani (HIP 14146)
Tau-3 Eridani is a white subgiant star in the constellation Eridanus. At 88 light years away, it shines at an apparent visual magnitude of 4.09. It is moving through the Galaxy at a speed of 22.5 km/s relative to the Sun.
Sky position: RA 3h 2.4m, Dec -23° 37.5'
Common designations: Tau-3 Eridani, 11 Eridani, HR 919, HD 18978, GJ 121, GJ 121.0, HIP 14146, Gaia DR3 5077970830842019584
Tau-3 Eridani has the spectral type A3IV-V. 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 Tau-3 Eridani in the sky
Tau-3 Eridani lies in Eridanus. With a declination of -23° 37.5', it is visible from the entire Southern Hemisphere and from the Northern Hemisphere up to about latitude 66° 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 Tau-3 Eridani
Astrometry and spectroscopy
| Right Ascension (J2000) | 45.59791400° (3h 2.4m) |
| Declination (J2000) | -23.62447172° (-23° 37.5') |
| Galactic Longitude | 213.53886764° |
| Galactic Latitude | -60.29670861° |
| Proper motion RA | -147.85 mas/yr |
| Proper motion Dec | -55.25 mas/yr |
| Parallax | 36.95 ± 0.15 mas |
| Spectral Type | A3IV-V |
| Radial Velocity | -9.80 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 4.33 | 2.17 |
| B | 4.25 | 2.09 |
| V | 4.09 | 1.93 |
| R | 3.96 | 1.80 |
| I | 3.87 | 1.71 |
| J | 3.77 | 1.61 |
| H | 3.68 | 1.52 |
| K | 3.66 | 1.50 |
Colour index B-V: +0.16
Derivations
- Heliocentric distance: 27.06 pc (88 light years) (0.4% margin of error)
- Absolute visual magnitude: 1.93
- Transverse velocity: 20.2 km/s
- Space velocity relative to the Sun: 22.5 km/s
- Galactic position (X, Y, Z): -11.2 pc, -7.4 pc, -23.5 pc
- Galactic velocity (U, V, W): 19.9 km/s, 10.4 km/s, -1.5 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.