Psi6 Aurigae
Binary star in the constellation Auriga
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Psi6 Aurigae is a spectroscopic binary[6] star system in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ψ6 Aurigae, and abbreviated Psi6 Aur or ψ6 Aur. This system is visible as a dim, naked eye star with an apparent visual magnitude of +5.22.[3] Based upon a measured annual parallax shift of 8.01 mas,[2] it is approximately 407 light-years (125 parsecs) distant from the Earth. The system is drifting closer to the Sun with a radial velocity of −6.5 km/s.[5]
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 06h 47m 39.576s[2] |
| Declination | +48° 47′ 22.14″[2] |
| Apparent magnitude (V) | +5.22[3] |
| Characteristics | |
| Evolutionary stage | red giant branch[2] |
| Spectral type | K0.5 III[4] |
| U−B color index | +1.04[3] |
| B−V color index | +1.11[3] |
| Variable type | Constant[1] |
| Astrometry | |
| Radial velocity (Rv) | −6.51±0.30[5] km/s |
| Proper motion (μ) | RA: +3.988 mas/yr[2] Dec.: +4.748 mas/yr[2] |
| Parallax (π) | 8.0121±0.1402 mas[2] |
| Distance | 407 ± 7 ly (125 ± 2 pc) |
| Absolute magnitude (MV) | +0.01[1] |
| Orbit[6] | |
| Period (P) | 5,996±26 d |
| Eccentricity (e) | 0.044±0.014 |
| Periastron epoch (T) | 52556 ± 310 MJD |
| Argument of periastron (ω) (secondary) | 222±19° |
| Semi-amplitude (K1) (primary) | 3.24±0.04 km/s |
| Details[7] | |
| ψ6 Aur A | |
| Mass | 2.02±0.28 M☉ |
| Radius | 17.72±0.76 R☉ |
| Luminosity | 123.4±10.2 L☉ |
| Surface gravity (log g) | 2.25±0.07 cgs |
| Temperature | 4,574±26 K |
| Metallicity [Fe/H] | −0.08±0.10 dex |
| Rotational velocity (v sin i) | +10[8] km/s |
| Age | 1.55±0.67 Gyr |
| Other designations | |
| ψ6 Aur, 57 Aurigae, BD+48°1436, FK5 1176, HD 48781, HIP 32562, HR 2487, SAO 41346[9] | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 5,996 days (16.4 years) and an eccentricity of 0.044.[6] The visible component is an evolved K-type giant star with a stellar classification of K0.5 III.[4] It is most likely (78% chance) on the red giant branch and is around 1.55 billion years old. As such, it has an estimated double the mass of the Sun and about 18 times the Sun's radius. The star is radiating about 123 times the Sun's luminosity from its photosphere at an effective temperature of 4,574 K.[7]