Magnitude 2.146 Apparent magnitude (V) 2.146 | ||
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Similar Alpha Gruis, Alpha Pavonis, Epsilon Carinae, Delta Velorum, Epsilon Scorpii | ||
Beta Gruis (β Gruis, β Gru) is the second brightest star in the southern constellation of Grus. It was once considered the rear star in the tail of the constellation of the (Southern) Fish: it, with α, δ, θ. ι, and λ Gru, belonged to Piscis Austrinus in medieval Arabic astronomy.
This is a red giant star with an estimated mass of about 2.4 times that of the Sun and a surface temperature of approximately 3,480 K, just over half the surface temperature of the Sun. This low temperature accounts for the dull red color of an M-type star. The total luminosity is about 2,500 times that of the Sun, and it has estimated 180 times the Sun's radius.
Beta Gruis is a type semiregular variable (SRb) star that varies in magnitude by about 0.4. It varies between intervals when it displays regular changes with a 37-day periodicity and times when it undergoes slow irregular variability.
Beta Gruis played a crucial part in Perth Observatory's tracking of comet 2000 WM1 LINEAR in December 2001.