The star Beta Centauri, the 11th-brightest star in the sky, also known as Agena. It is a B1 giant of magnitude 0.6, but is a variable of the Beta Cephei variety with an amplitude of only about 0.05 mag. It is a double, with a close companion of magnitude 3.9. Hadar lies 392 l.y. away.
Subjects: Astronomy and Astrophysics.