Psi9 Aurigae
Star in the constellation Auriga
From Wikipedia, the free encyclopedia
Psi9 Aurigae is a star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from ψ9 Aurigae, and abbreviated Psi9 Aur or ψ9 Aur. This star is dimly visible to the naked eye with an apparent visual magnitude of 5.75. Based upon an annual parallax shift of 3.45 mas, the distance to this star is approximately 950 light-years (290 parsecs). It is drifting closer to the Sun with a radial velocity of −41 km/s.[6] This is most likely (88.5% chance) a runaway star, having a peculiar velocity of 31.8+14.6
−12.4 km/s.[11]
 | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 06h 56m 32.05797s[2] |
| Declination | +46° 16′ 26.3957″[2] |
| Apparent magnitude (V) | 5.75[3] |
| Characteristics | |
| Spectral type | B8 IIIe[4] |
| U−B color index | −0.46[5] |
| B−V color index | −0.06[5] |
| Astrometry | |
| Radial velocity (Rv) | −41.1±2.9[6] km/s |
| Proper motion (μ) | RA: −3.263 mas/yr[2] Dec.: +5.040 mas/yr[2] |
| Parallax (π) | 3.4481±0.0560 mas[2] |
| Distance | 950 ± 20 ly (290 ± 5 pc) |
| Absolute magnitude (MV) | −2.03[1] |
| Details | |
| Mass | 2.4[7] M☉ |
| Radius | 3.7[3] R☉ |
| Luminosity | 868[1] L☉ |
| Surface gravity (log g) | 2.71[7] cgs |
| Temperature | 9,573[7] K |
| Metallicity [Fe/H] | −0.55[8] dex |
| Rotational velocity (v sin i) | 235[9] km/s |
| Other designations | |
| ψ9 Aur, BD+46 1203, HD 50658, HIP 33377, HR 2568, SAO 41446[10] | |
| Database references | |
| SIMBAD | data |
The spectrum of Psi9 Aurigae matches a giant star with a stellar classification of B8 IIIe.[4] The 'e' suffix indicates this is a Be star that shows emission lines of hydrogen in its spectrum. This is caused by a circumstellar shell of hot gas. The emission undergoes variability on a time scale of sixteen years.[4] This star is spinning rapidly with a projected rotational velocity of 235 km/s.[9] It has 2.4[7] times the mass of the Sun and 3.7 times the Sun's radius.[3] ψ9 Aur is radiating 868[1] times the luminosity of the Sun from its photosphere at an effective temperature of 9,573 K.[7]