Menkalinan (Beta Aurigae)

Beta Aurigae

Menkalinan (Beta Aurigae) is the third brightest star in the constellation Auriga. Its Arabic name (also written as Menkarlina) means "the shoulder of the rein-holder." Menkalinan lies just 0.5 arcminute away from the solstitial colure, the great circle in the sky that passes through both celestial poles and the summer and winter solstices. Menkalinan is a binary system consisting of two almost identical subgiant A stars in a tight orbit that, every 3.96 days, results in a partial eclipse of one star by the other by about a tenth of a magnitude. The twins, each about 48 times more luminous than the Sun, are separated by only about one-fifth the distance between the Sun and Mercury. So close are they, that they distort each other into an ellipsoidal shape through mutual tides. A faint red dwarf, well below naked-eye visibility, appears to orbit the pair at least 330 AU (astronomical units) away.


visual magnitude 1.90
absolute magnitude -0.11
spectral type A2V
surface temperature 9,200 K
luminosity 95 Lsun
distance 82 light-years
position RA 05h 59m 32s,
Dec +44° 56' 51"