Beta Centauri (β Cen, β Centauri) is a star system in the southern constellation of Centaurus. With an apparent visual magnitude of 0.60, it is 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 word for "ground / soil / earth" (from أل أرض - al ardh)[6] or "civilization" (from ألحضارة - al hidaara), while the name Agena comes from Latin words for "the knee". The Chinese name for the star is 马腹一 (Mandarin: mǎ fù yī, the First Star of the Horse's Abdomen).[8]
Beta Centauri is well known in the Southern Hemisphere as the inner of the two "Pointers" to the Southern Cross. A line made from the other pointer, Alpha Centauri, through Beta Centauri leads to within a few degrees of Gacrux, the star at the top of the cross. Using Gacrux, a navigator can draw a line with Acrux to effectively determine south.[9]
The indigenous Boorong people of northwestern Victoria named it as Bermbermgle (together with α Cen).[10]
Excerpt from Wikipedia.