Eta Arae

Eta Arae is a single star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from η Arae, and abbreviated Eta Ara or η Ara. This star is visible to the naked eye with an apparent visual magnitude of 3.76. Based on parallax measurements, it is approximately distance from Earth. The star is moving away from the Sun with a radial velocity of +9 km/s.
The spectrum of this star matches a stellar classification of K5 III, indicating that, at an estimated age of five billion years, it has reached the giant star stage of its evolution. With 1.12 times the mass of the Sun, it has an outer envelope that has expanded to 40 times the Sun's radius. The star is now spinning so slowly that it takes more than eleven years to complete a single rotation. Eta Arae is radiating energy into space from its photosphere with 575 times the Sun's luminosity at an effective temperature of 4,147 K, giving it the orange-hued glow of a K-type star.
It has a magnitude 13.5 optical companion, located 23.4 arcseconds away along a position angle of 118°, as of 2000.