Tau Aurigae, a yellow giant star in Auriga
Tau Aurigae is a yellow giant star in the constellation Auriga. At 210 light years away, it shines at an apparent visual magnitude of 4.50.
Tau Aurigae (HIP 27483)
Tau Aurigae is a yellow giant star in the constellation Auriga. At 210 light years away, it shines at an apparent visual magnitude of 4.50. It is moving through the Galaxy at a speed of 21.8 km/s relative to the Sun.
Sky position: RA 5h 49.2m, Dec +39° 10.9'
Common designations: Tau Aurigae, 29 Aurigae, HR 1995, HD 38656, Gaia DR3 191419859094194816, HIP 27483
Tau Aurigae has the spectral type G8IIIbFe-1. G-type stars are yellow stars of about 5,300 to 6,000 K, the same class as the Sun. Their spectra show strong lines of ionized calcium and many metals. 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 Tau Aurigae in the sky
Tau Aurigae lies in Auriga. With a declination of +39° 10.9', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 51° S. Observers poleward of latitude 51° N 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 January, which makes the weeks around that month the best time to observe it.
Tabulated data for Tau Aurigae
Astrometry and spectroscopy
| Right Ascension (J2000) | 87.29348991° (5h 49.2m) |
| Declination (J2000) | 39.18107232° (+39° 10.9') |
| Galactic Longitude | 171.58394428° |
| Galactic Latitude | 5.90914042° |
| Proper motion RA | -28.27 mas/yr |
| Proper motion Dec | -25.06 mas/yr |
| Parallax | 15.55 ± 0.12 mas |
| Spectral Type | G8IIIbFe-1 |
| Radial Velocity | -18.47 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 6.16 | 2.12 |
| B | 5.45 | 1.41 |
| V | 4.50 | 0.46 |
| R | 3.80 | -0.24 |
| I | 3.31 | -0.73 |
| J | 2.89 | -1.15 |
| H | 2.43 | -1.61 |
| K | 2.32 | -1.72 |
Colour index B-V: +0.95
Derivations
- Heliocentric distance: 64.31 pc (210 light years) (0.8% margin of error)
- Absolute visual magnitude: 0.46
- Transverse velocity: 11.5 km/s
- Space velocity relative to the Sun: 21.8 km/s
- Galactic position (X, Y, Z): -63.3 pc, 9.4 pc, 6.6 pc
- Galactic velocity (U, V, W): 16.7 km/s, -4.7 km/s, -13.1 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.