Beta Centauri (β Cen, β Centauri) is a trinary
star system in the southern
constellation of
Centaurus. The system's combined
apparent visual magnitude of 0.61, makes it the second brightest star in the
constellation Centaurus and the
tenth brightest star in the night sky. It has the traditional names
Hadar and
Agena. The name
Hadar comes from the
Arabic حضار (the root's meaning is "to be present" or "on the ground" or "settled, civilized area"), while the name
Agena may ultimately be derived from the
Latin gena 'knees'. The Chinese name for the star is 马腹一 (
Mandarin: mǎ fù yī,
the First Star of the Horse's Abdomen).