Beta Aurigae
Binary star system in the northern constellation of Auriga
- 2 min read
- 2 chapters
Related on Lably
Through Constellation, Parsec and Light-year
Along their respective orbits around the Milky Way, Beta Aurigae and the Sun are closing in on each other, so that in around one million years it will become the brightest star in the night sky. It is predicted to come as close as 31.7 ly (9.72 pc) in 1.31 million years.
Nomenclature
β Aurigae is the star system's Bayer designation. The traditional name Menkalinan is derived from the Arabic منكب ذي العنان mankib ðī-l-‘inān "shoulder of the rein-holder". In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included Menkalinan for Beta Aurigae Aa.
It is known as 五車三 (the Third Star of the Five Chariots) in traditional Chinese astronomy.
Sign in to keep reading
One more chapter is free with a Lably account.
Properties
Beta Aurigae is a binary star system, but it appears as a single star in the night sky. The two stars are metallic-lined stars belonging to the A-type stellar classification. Although the spectra have the luminosity class of a subgiant (IV), the components are still on the main sequence stage of evolution. This discrepancy arises from their nature as Am stars, which make them larger and more luminous than a "normal" star. A-type stars are hot and release a white hued light; these two stars burn brighter and with more heat than the Sun, which is a G2-type main sequence star. The pair constitute an eclipsing spectroscopic binary; the combined apparent magnitude varies over a period of 3.96 days between +1.89 and +1.94, as every 47.5 hours one of the stars partially eclipses the other from Earth's perspective. The two stars are designated Aa and Ab in modern catalogues, but have also been referred to as components 1 and 2 or A and B.
There is an 11th magnitude optical companion with a separation of 187″ as of 2011, but increasing. It is also an A-class subgiant, but is an unrelated background star.
At an angular separation of 13.9±0.3 arcseconds along a position angle of 155° is a companion star that is 8.5 magnitudes fainter than the primary. It may be the source of the X-ray emission from the vicinity. The Beta Aurigae system is believed to be a stream member of the Ursa Major Moving Group.