Astronomy:Sigma Aurigae
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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[2] mas/yr Dec.: −10.953[2] mas/yr |
| Parallax (π) | 6.3543 ± 0.0892[2] mas |
| 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 | |
| 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
- ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. XHIP record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 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.
- ↑ 3.0 3.1 3.2 3.3 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, doi:10.1093/mnras/133.4.475, Bibcode: 1966MNRAS.133..475A.
- ↑ 4.0 4.1 Abt, H. A. (September 1985), "Visual multiples. VIII - 1000 MK types", Astrophysical Journal Supplement Series 59: 95–112, doi:10.1086/191064, Bibcode: 1985ApJS...59...95A.
- ↑ 5.0 5.1 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, doi:10.1051/0004-6361:20041272, Bibcode: 2005A&A...430..165F.
- ↑ 6.0 6.1 6.2 6.3 6.4 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 7.0 7.1 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, doi:10.1086/191527, Bibcode: 1990ApJS...74.1075M.
- ↑ 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. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=sig+Aur.
- ↑ 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, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M.
- ↑ Star Names: Their Lore and Meaning (Reprint ed.), New York, NY: Dover Publications Inc, 1963, p. 91, ISBN ((0-486-21079-0)), https://archive.org/details/starnamestheirlo00alle/page/91, retrieved 2010-12-12.
- ↑ 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, https://ntrs.nasa.gov/citations/19720005197, retrieved 2025-05-16.
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