Astronomy:Chi Aurigae
Coordinates: 
05h 32m 43.7s, +32° 11′ 31.3″
  | |
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Auriga |
| Right ascension | 05h 32m 43.67437s[1] |
| Declination | +32° 11′ 31.2805″[1] |
| Apparent magnitude (V) | 4.74[2] |
| Characteristics | |
| Spectral type | B5 Iab[3] |
| U−B color index | −0.44[2] |
| B−V color index | +0.32[2] |
| Astrometry | |
| Radial velocity (Rv) | 7.27±5.21[1] km/s |
| Proper motion (μ) | RA: −0.812[1] mas/yr Dec.: −3.15[1] mas/yr |
| Parallax (π) | 0.9087 ± 0.1906[1] mas |
| Distance | 3,910±420 ly (1,200±130 pc) |
| Absolute magnitude (MV) | −6.4[4] |
| Orbit[4] | |
| Period (P) | 676.85 ± 0.21 d |
| Eccentricity (e) | 0.116 ± 0.048 |
| Longitude of the node (Ω) | 181.7° ± 24.3° |
| Periastron epoch (T) | 2422754.2 ± 46.1 HJD |
| Semi-amplitude (K1) (primary) | 22.0 ± 2.9 km/s |
| Details | |
| Mass | 21.1±0.2[5] M☉ |
| Radius | 68±8[5] R☉ |
| Luminosity | 190,500+49,300 −39,200[5] L☉ |
| Surface gravity (log g) | 2.11±0.06[5] cgs |
| Temperature | 14,600±300[5] K |
| Rotational velocity (v sin i) | 40[6] km/s |
| Age | 8.7[5] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Chi Aurigae is a binary star system in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from χ Aurigae, and abbreviated Chi Aur or χ Aur. This star is visible to the naked eye with an apparent visual magnitude of 4.74.[2] The brightness of the star is diminished by 1.26 in magnitude from extinction caused by intervening gas and dust.[4] It is a member of the Aur OB1 association of co-moving stars.[4]
Chi Aurigae is a single-lined spectroscopic binary with an orbital period of 676.85 d and an eccentricity of 0.116.[4] The primary component of this system is a supergiant star with a stellar classification of B5 Iab.[3] It is over 190,000 times more luminous, around 20 times more massive and around 70 times larger than the Sun. The photosphere has an effective temperature of 14,600 K.[5] Its stellar wind is causing mass loss at the rate of (0.38–0.46)×10−9 solar masses per year, or the equivalent of the Sun's mass every 2.4 billion years.[8]
The distance of Chi Aurigae is determined at 3,900 light-years based on spectroscopic observations.[5] Parallax measurements by the Hipparcos spacecraft were unsuccessful because the parallax error was bigger than the value itself,[9] while the Gaia spacecraft measured the parallax with a 22% error, giving a distance of 3,590±750 ly.[1]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Crawford, D. L. et al. (1971), "Four-color, H-beta, and UBV photometry for bright B-type stars in the northern hemisphere", The Astronomical Journal 76: 1058, doi:10.1086/111220, Bibcode: 1971AJ.....76.1058C.
- ↑ 3.0 3.1 Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode: 1968ApJS...17..371L.
- ↑ 4.0 4.1 4.2 4.3 4.4 Raja, Tomas; Wolf, Marek (March 1998), "Hα variability of the B-type binary chi Aurigae", Astronomy and Astrophysics 331: 550–556, Bibcode: 1998A&A...331..550R.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 Weßmayer, D. et al. (December 2022), "Quantitative spectroscopy of B-type supergiants" (in en), Astronomy & Astrophysics 668: A92, doi:10.1051/0004-6361/202243973, ISSN 0004-6361, Bibcode: 2022A&A...668A..92W
- ↑ Abt, Helmut A. et al. (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal 573 (1): 359–365, doi:10.1086/340590, Bibcode: 2002ApJ...573..359A.
- ↑ "* chi Aur". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+chi+Aur.
- ↑ Prinja, R. K.; Massa, D. L. (October 2010), "Signature of wide-spread clumping in B supergiant winds", Astronomy and Astrophysics 521: L55, doi:10.1051/0004-6361/201015252, Bibcode: 2010A&A...521L..55P.
- ↑ van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. Note: see VizieR catalogue I/311.
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