Rho Aurigae, a blue-white main-sequence star in Auriga
Rho Aurigae is a blue-white main-sequence star in the constellation Auriga. At 627 light years away, it shines at an apparent visual magnitude of 5.21.
Rho Aurigae (HIP 25048)
Rho Aurigae is a blue-white main-sequence star in the constellation Auriga. At 627 light years away, it shines at an apparent visual magnitude of 5.21. It is moving through the Galaxy at a speed of 40.4 km/s relative to the Sun.
Sky position: RA 5h 21.8m, Dec +41° 48.3'
Common designations: Rho Aurigae, 20 Aurigae, HR 1749, HD 34759, HIP 25048, Gaia DR3 195012444618313856
Rho Aurigae has the spectral type B4V. B-type stars are hot (about 10,000 to 30,000 K), luminous and blue-white. They are massive, short-lived stars, typically only tens of millions of years old, and are common in young clusters and OB associations. Its luminosity class V means it is a main-sequence (dwarf) star, still fusing hydrogen into helium in its core like the Sun.
How to find Rho Aurigae in the sky
Rho Aurigae lies in Auriga. With a declination of +41° 48.3', it is visible from the entire Northern Hemisphere and from the Southern Hemisphere down to about latitude 48° S. Observers poleward of latitude 48° 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 Rho Aurigae
Astrometry and spectroscopy
| Right Ascension (J2000) | 80.45173560° (5h 21.8m) |
| Declination (J2000) | 41.80457204° (+41° 48.3') |
| Galactic Longitude | 166.56516356° |
| Galactic Latitude | 2.92699834° |
| Proper motion RA | 15.05 mas/yr |
| Proper motion Dec | -37.70 mas/yr |
| Parallax | 5.20 ± 0.13 mas |
| Spectral Type | B4V |
| Radial Velocity | 16.30 km/s |
Photometry
| Band | Magnitude | Abs. Mag. |
|---|---|---|
| B | 5.07 | -1.35 |
| V | 5.21 | -1.21 |
| J | 5.44 | -0.98 |
| H | 5.53 | -0.89 |
| K | 5.58 | -0.84 |
Colour index B-V: -0.14
Derivations
- Heliocentric distance: 192.20 pc (627 light years) (2.6% margin of error)
- Absolute visual magnitude: -1.21
- Transverse velocity: 37.0 km/s
- Space velocity relative to the Sun: 40.4 km/s
- Galactic position (X, Y, Z): -186.7 pc, 44.6 pc, 9.8 pc
- Galactic velocity (U, V, W): -24.6 km/s, -31.2 km/s, -7.3 km/s
Data: Extended Hipparcos Compilation (XHIP) and SIMBAD.