Mu Arae (μ Arae, abbreviated Mu Ara, μ Ara) is a yellow main-sequence star located in the constellation Ara, approximately 50 light-years (15 parsecs) from Earth. It is the brightest star in the constellation and is easily visible to the naked eye under dark skies.
Mu Arae is a slightly older and more massive star than the Sun, with a mass of about 1.08 solar masses and a radius of about 1.02 solar radii. It has a surface temperature of about 5,733 K (5,460 °C; 9,822 °F), which is slightly cooler than the Sun.
Mu Arae is a metal-rich star, with a metallicity of about 0.23. This means that it has 23% more heavy elements than the Sun. Metal-rich stars are thought to be more likely to have planets, and Mu Arae is no exception.
Mu Arae has four known planets, all of which are gas giants. The planets are named Mu Arae b, c, d, and e. The planets orbit Mu Arae at distances of 0.921 AU, 0.74 AU, 5.235 AU, and 14.5 AU, respectively.
Mu Arae b, c, and d are all hot Jupiters, meaning that they are gas giants that orbit their star very closely. Mu Arae e is a cold Jupiter, meaning that it is a gas giant that orbits its star at a greater distance.
Mu Arae is a young star system, with an estimated age of about 2.5 billion years. This makes it a valuable target for studies of planet formation and evolution.