Beta Centauri

Starbox begin
name=β Centauri Starbox observe
epoch=J2000
constell=Centaurus
ra=RA|14|03|49.4
dec=DEC|−60|22|23
appmag_v=0.60 Starbox character
class=B1III
b-v=−0.22
u-b=−0.98
variable=β Cep Starbox astrometry
radial_v=5.9
prop_mo_ra=−33.96
prop_mo_dec=−2.506
parallax=6.21
p_error=0.56
absmag_v=−5.42 Starbox detail
mass = 12 M
luminosity = 11200 | Starbox catalog
names=Agena, Hadar, Khadar, HR 5267, HD 122451, CD−59°5365, LHS 51, SAO 252582, HIP 68702, GC 18971, CCDM J14038-6022 Starbox reference
Simbad=HD+122451

Beta Centauri (β Cen / β Centauri), also known as Hadar or Agena, is the second brightest star in the constellation Centaurus and the tenth brightest star in the night sky. Beta Centauri is a B1 III blue-white giant star that the astrometric Hipparcos satellite calculates as about 161 parsecs or 525 light-years from the solar system. The name "Hadar" comes from the Arabic word for "ground", while the name "Agena" comes from Latin words for "the knee".

In 1935, J.G. Voute identified Beta Centauri as a double star, giving it the identifier VOU 31. The companion is separated from the primary by 1.3", and has remained so since the discovery, although the position angle has changed slightly. This would indicate that the orbital period is very long, if the pair are actually gravitationally associated. The primary is also a spectroscopic binary, having at least one companion with an orbital period of 352 days, and possibly other companions.

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.