Sigma Aurigae, Latinized from σ Aurigae, is a

giant star A giant star is a star with substantially larger radius and luminosity than a main-sequence (or ''dwarf'') star of the same surface temperature.Giant star, entry in ''Astronomy Encyclopedia'', ed. Patrick Moore, New York: Oxford University Press ...

in the northern constellation of Auriga. It is faintly visible to the naked eye with an

apparent visual magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's lig ...

of 4.99. With an annual

parallax Parallax is a displacement or difference in the apparent position of an object viewed along two different lines of sight and is measured by the angle or semi-angle of inclination between those two lines. Due to foreshortening, nearby object ...

shift of 6.21 mas, it is approximately distant from the Earth. This is an

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation te ...

giant star with a

stellar classification In astronomy, stellar classification is the classification of stars based on their spectral characteristics. Electromagnetic radiation from the star is analyzed by splitting it with a prism or diffraction grating into a spectrum exhibiting t ...

of K4 III. Sigma Aurigae has a 12th magnitude companion at an

angular separation Angular distance \theta (also known as angular separation, apparent distance, or apparent separation) is the angle between the two sightlines, or between two point objects as viewed from an observer. Angular distance appears in mathematics (in pa ...

of 8

arcsecond A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...

s, as well as two fainter companions at 28 and 35" respectively. All are background objects, stars much further away than Sigma itself. Sigma Aurigae, along with λ Aur and μ Aur, were Kazwini's ''Al Ḣibāʽ'' (ألحباع), the Tent. 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''.

References

External links

HR 1773

CCDM J05247+3723

Image Sigma Aurigae
{{DEFAULTSORT:Sigma Aurigae 035186 Double stars 025292 Aurigae, Sigma Auriga (constellation) K-type giants Aurigae, 21

1773 Events January–March * January 1 – The hymn that becomes known as ''Amazing Grace'', at this time titled "1 Chronicles 17:16–17", is first used to accompany a sermon led by curate John Newton in the town of Olney, Bucking ...

Durchmusterung objects