Upsilon Aurigae, a red giant star in Auriga
Upsilon Aurigae is a red giant star in the constellation Auriga. At 569 light years away, it shines at an apparent visual magnitude of 4.74.
Upsilon Aurigae (HIP 27639)
Upsilon Aurigae is a red giant star in the constellation Auriga. At 569 light years away, it shines at an apparent visual magnitude of 4.74. It is moving through the Galaxy at a speed of 61.2 km/s relative to the Sun.
Sky position: RA 5h 51.0m, Dec +37° 18.3'
Common designations: Upsilon Aurigae, 31 Aurigae, HR 2011, HD 38944, HIP 27639, Gaia DR3 3456177332896378496
Upsilon Aurigae has the spectral type M0III. M-type stars are cool red stars below about 3,900 K whose spectra are dominated by titanium oxide molecular bands. Red dwarfs, red giants and red supergiants all fall in this class. 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 Upsilon Aurigae in the sky
Upsilon Aurigae lies in Auriga. With a declination of +37° 18.3', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 53° S. Observers poleward of latitude 53° 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 Upsilon Aurigae
Astrometry and spectroscopy
| Right Ascension (J2000) | 87.76015537° (5h 51.0m) |
| Declination (J2000) | 37.30556969° (+37° 18.3') |
| Galactic Longitude | 173.39555624° |
| Galactic Latitude | 5.27583548° |
| Proper motion RA | 36.43 mas/yr |
| Proper motion Dec | -45.61 mas/yr |
| Parallax | 5.74 ± 0.21 mas |
| Spectral Type | M0III |
| Radial Velocity | 37.67 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| U | 8.29 | 2.08 |
| B | 6.36 | 0.15 |
| V | 4.74 | -1.47 |
| R | 3.38 | -2.83 |
| I | 2.31 | -3.90 |
| J | 1.65 | -4.56 |
| H | 0.86 | -5.34 |
| K | 0.60 | -5.61 |
Colour index B-V: +1.62
Derivations
- Heliocentric distance: 174.34 pc (569 light years) (3.6% margin of error)
- Absolute visual magnitude: -1.47
- Transverse velocity: 48.2 km/s
- Space velocity relative to the Sun: 61.2 km/s
- Galactic position (X, Y, Z): -172.5 pc, 20.0 pc, 16.0 pc
- Galactic velocity (U, V, W): -42.1 km/s, -43.2 km/s, 10.4 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.