Sigma Aurigae
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Auriga[1] |
| Right ascension | 05h 24m 39.141s[2] |
| Declination | +37° 23′ 07.26″[2] |
| Apparent magnitude (V) | 4.99[3] |
| Characteristics | |
| Spectral type | K3III CN+2[4] |
| U−B color index | +1.75[3] |
| B−V color index | +1.42[3] |
| Astrometry | |
| Radial velocity (Rv) | −19.7[5] km/s |
| Proper motion (μ) | RA: −0.564 mas/yr[2] Dec.: −10.953 mas/yr[2] |
| Parallax (π) | 6.3543±0.0892 mas[2] |
| Distance | 513 ± 7 ly (157 ± 2 pc) |
| Absolute magnitude (MV) | −0.75[1] |
| Details | |
| Radius | 43.72+1.08 −3.24[6] R☉ |
| Luminosity | 496±20[6] L☉ |
| Surface gravity (log g) | 1.75[7] cgs |
| Temperature | 4,120+162 −50[6] K |
| Metallicity [Fe/H] | −0.03[7] dex |
| Rotational velocity (v sin i) | 10[8] km/s |
| Other designations | |
| σ Aur, 21 Aurigae, BD+37°1175, GC 6636, HD 35186, HIP 25292, HR 1773, SAO 57981, PPM 70308, WDS J05247+3723A[9] | |
| Database references | |
| SIMBAD | data |
Sigma Aurigae is a star in the northern constellation of Auriga. Its name is a Bayer designation that is Latinized from σ Aurigae, and abbreviated Sigma Aur or σ Aur. This star is faintly visible to the naked eye with an apparent visual magnitude of 4.99.[3] With an annual parallax shift of 6.35 mas,[2] it is approximately 530 light-years (160 parsecs) distant from the Earth. It is drifting closer to the Sun with a radial velocity of −20 km/s.[5]
This is an evolved giant star with a stellar classification of K3III CN+2,[4] indicating that it has exhausted the supply of hydrogen at its core. The 'CN+2' notation indicates anomalously strong lines of the CN molecule in the spectrum. This star has expanded to 44 times the radius of the Sun and is radiating nearly 500[6] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,120 K.[6] There is a 12th magnitude companion at an angular separation of 8 arcseconds, as well as two fainter companions at 28 and 35" respectively.[10] All are background objects, stars much further away than Sigma itself.[citation needed]
Sigma Aurigae, along with λ Aur and μ Aur, were Kazwini's Al Ḣibāʽ (ألحباع), the Tent.[11] According to the catalogue of stars in the Technical Memorandum 33-507 – A Reduced Star Catalog Containing 537 Named Stars, Al Ḣibāʽ were the title for three stars: λ Aur as Al Ḣibāʽ I, μ Aur as Al Ḣibāʽ II and σ Aur as Al Ḣibāʽ III.[12]
References
[edit]- ^ a b Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. XHIP record for this object at VizieR.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d Argue, A. N. (1966), "UBV photometry of 550 F, G and K type stars", Monthly Notices of the Royal Astronomical Society, 133 (4): 475–493, Bibcode:1966MNRAS.133..475A, doi:10.1093/mnras/133.4.475.
- ^ a b Abt, H. A. (September 1985), "Visual multiples. VIII - 1000 MK types", Astrophysical Journal Supplement Series, 59: 95–112, Bibcode:1985ApJS...59...95A, doi:10.1086/191064.
- ^ a b Famaey, B.; et al. (January 2005), "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters", Astronomy and Astrophysics, 430 (1): 165–186, arXiv:astro-ph/0409579, Bibcode:2005A&A...430..165F, doi:10.1051/0004-6361:20041272, S2CID 17804304.
- ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
- ^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1): 1, Bibcode:1970CoAsi.239....1B.
- ^ "sig Aur", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2012-08-22.
- ^ Mason, Brian D.; et al. (2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- ^ Allen, R. H. (1963), Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, p. 91, ISBN 0-486-21079-0, retrieved 2010-12-12.
{{citation}}: CS1 maint: ignored ISBN errors (link) - ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, California Institute of Technology: Jet Propulsion Laboratory, retrieved 2025-05-16.
