Beta Arae

Beta Arae (β Ara, β Arae) is the brightest star in the constellation Ara, with an apparent visual magnitude of 2.8. Parallax measurements place it at a distance of roughly 650 light-years (200 parsecs) from Earth.

The spectrum of this star matches a stellar classification of K3 Ib-IIa, with the luminosity class notation 'Ib-IIa' indicating that the star lies part way between a higher luminosity bright giant (IIa) and a lower luminosity supergiant (Ib). This represents two of the evolutionary stages that a massive star passes through after it has exhausted the hydrogen at its core. Beta Arae is radiating energy from its outer envelope at an effective temperature of 4,200 K, which causes it to take on the orange hue of a K-type star. This enlarged star appears to be rotating slowly with a projected rotational velocity of about 5 km/s. The abundance of elements other than hydrogen and helium, what astronomer term the star's metallicity, is more than three times the abundance in the Sun.