By: Ryan Jackson
Agena is a star that has many different names. A couple examples are Hadar and Beta Centauri. Agena is the eleventh brightest star in the the sky and is the second brightest star in the constellation Centaurus. Agena is about 525 light years away from the earth. Agena is more luminous and than the sun. The mass of the star is 10.7 ± 0.1. The spectral type or color of the star is a blue-white mix, which would be classified as spectral type B. The chart below shows that this means the star is approximately 20,000 K.
Agena/Hadar is part of a constellation named Centaurus. Centaurus is a bright constellation in the southern sky and is one of the largest. The origin of the name Agena means the "knee" of the centaur.