5 Aurigae
Triple star system in the constellation Auriga
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5 Aurigae is a triple star[6] system in the northern constellation of Auriga,[9] located about 178 light years away from the Sun based on parallax.[2] It is just visible to the naked eye as a dim, yellow-white hued star with an apparent visual magnitude of 5.95.[1] The system is moving away from the Earth with a heliocentric radial velocity of +8 km/s,[2] having come within 62.4 light-years some 8.7 million years ago.[1]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 05h 00m 18.33965s[2] |
| Declination | +39° 23′ 40.9392″[2] |
| Apparent magnitude (V) | 5.95[1] (6.02 + 9.50)[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F5 V[4] |
| Apparent magnitude (G) | 5.88[2] |
| U−B color index | −0.03[5] |
| B−V color index | +0.42[5] |
| Astrometry | |
| Radial velocity (Rv) | +7.92±0.13[2] km/s |
| Proper motion (μ) | RA: −10.609±0.171[2] mas/yr Dec.: −2.561±0.120[2] mas/yr |
| Parallax (π) | 18.3645±0.1215 mas[2] |
| Distance | 178 ± 1 ly (54.5 ± 0.4 pc) |
| Absolute magnitude (MV) | +2.07[1] |
| Orbit[6] | |
| Period (P) | 1,598.04±50.35 yr |
| Semi-major axis (a) | 5.379±0.388″ |
| Eccentricity (e) | 0.536±0.031 |
| Inclination (i) | 56.1±0.8° |
| Longitude of the node (Ω) | 155.4±0.7° |
| Periastron epoch (T) | 3,242.73±8.96 |
| Argument of periastron (ω) (secondary) | 333.4±4.5° |
| Details | |
| 5 Aur A | |
| Mass | 1.48[7] or 1.70[6] M☉ |
| Luminosity | 12.46[1] L☉ |
| Surface gravity (log g) | 4.14[7] cgs |
| Temperature | 6,603±225[7] K |
| Metallicity [Fe/H] | −0.02±0.07[8] dex |
| Age | 2.205[7] Gyr |
| 5 Aur B | |
| Mass | 0.82[6] M☉ |
| Other designations | |
| BD+39°1133, GC 6084, HD 31761, HIP 23261, HR 1599, SAO 57559, PPM 69817, ADS 3589, CCDM J05003+3924, WDS J05003+3924, TYC 2899-369-1[9] | |
| Database references | |
| SIMBAD | data |
This was initially discovered to be a binary star system by Otto Struve. The outer pair has an orbital period of 1,598 years with an eccentricity of 0.536.[6] The magnitude 6.02[3] primary, component A, is itself a binary system consisting of two stars of similar mass, roughly 1.5 times the mass of the Sun each, with an orbital period of 8.08 years.[10] It has a stellar classification of F5 V,[4] matching an F-type main-sequence star.
As of 2017, component B is a magnitude 9.50 star at an angular separation of 4.10″ from the primary along a position angle of 285°.[3]