Sigma Aurigae

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Template:Short description

σ Aurigae
Template:Location mark
Location of σ Aurigae (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Auriga[1]
Right ascension Template:RA[2]
Declination Template:DEC[2]
Apparent magnitude (V) 4.99[3]
Characteristics
Spectral type K3III CN+2[4]
U−B Template:Engvar +1.75[3]
B−V Template:Engvar +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]
DistanceTemplate:Rnd ± Template:Rnd ly
(Template:Rnd ± Template:Rnd pc)
Absolute magnitude (MV)−0.75[1]
Details
RadiusTemplate:Val[6] Template:Solar radius
LuminosityTemplate:Val[6] Template:Solar luminosity
Surface gravity (log g)1.75[7] cgs
TemperatureTemplate:Val[6] K
Metallicity [Fe/H]−0.03[7] dex
Rotational velocity (v sin i)10[8] km/s
Metallicity [Fe/H]{{{metal_fe2}}} dex
Other designations
Template:Odlist[9]
Database references
SIMBADdata

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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 Template:Convert 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.Script error: No such module "Unsubst".

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

Template:Reflist

External links

Template:Stars of Auriga

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  12. Cite error: Invalid <ref> tag; no text was provided for refs named rhoads1971