from Earth. This star is around 9.6 times as massive as the Sun, and has an average of 4.5 times its radius. It is 5,800 times as luminous as the Sun, its energy emitted from its outer envelope at an effective temperature of 18,044 K. A Be star, Alpha Arae is surrounded by a dense equatorial disk of material in Keplerian (rather than uniform) rotation. The star is losing mass by a polar stellar wind with a terminal velocity of approximately 1,000 km/s. The third brightest star in Ara at magnitude 3.13 is Zeta Arae, an orange giant of spectral type K3III that is located 490 ± 10 light-years from Earth. Around 7–8 times as massive as the Sun, it has swollen to a diameter around 114 times that of the Sun and is 3800 times as luminous. Were it not dimmer by intervening interstellar dust, it would be significantly brighter at magnitude 2.11. Delta Arae is a blue-white main sequence star of spectral type B8Vn and magnitude 3.6, 198 ± 4 light-years from Earth. It is around 3.56 times as massive as the Sun. Epsilon1 Arae is an orange giant of apparent magnitude 4.1, 360 ± 10 light-years distant from Earth. It is around 74% more massive than the Sun. At an age of about 1.7 billion years, the outer envelope of the star has expanded to almost 34 times the Sun's radius. Eta Arae is an orange giant of apparent magnitude 3.76, located 299 ± 5 light-years distant from Earth. Estimated to be around five billion years old, 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. GX 339-4 (V821 Arae) is a moderately strong variable galactic low-mass X-ray binary (LMXB) source and black-hole candidate that flares from time to time. From spectroscopic measurements, the mass of the black-hole was found to be at least of 5.8 solar masses. Exoplanets have been discovered in seven star systems in the constellation. Mu Arae (Cervantes) is a sunlike star that hosts four planets. HD 152079 is a sunlike star with a jupiter-like planet with an orbital period of 2097 ± 930 days. HD 154672 is an ageing sunlike