Mu Aquarii
Mu Aquarii is the for a binary star system in the equatorial constellation of Aquarius. Its name is a Bayer designation that is Latinized from μ Aquarii, and abbreviated Mu Aqr or μ Aqr. The star is visible to the naked eye with a combined apparent visual magnitude of 4.7. Based upon parallax measurements, the distance to this system is about. It is drifting closer to the Sun with a radial velocity of −9.1 km/s.
This star was tentatively identified as a single-lined spectroscopic binary by Helmut A. Abt in 1961. It has an orbital period of and an eccentricity of 0.23. The pair have been resolved by speckle interferometry, showing an angular separation of.
The visible spectrum matches a stellar classification of A3m, with the 'm' suffix indicating that this is an Am, or chemically peculiar star. A 2020 classification of, indicates ionized calcium lines match a class of A4, hydrogen lines a class of F1, and metal lines F3. There are also abundance anomalies of europium and strontium. The primary has double the mass of the Sun and 3.5 times the Sun's radius, It is radiating 26 times the luminosity of the Sun from its photosphere at an effective temperature of 6,906 K.
This star together with ν Aquarii is Albulaan, derived from an Arabic term al-bulaʽān meaning "the two swallowers". This star, along with ε Aqr and ν Aqr, were al Bulaʽ, the Swallower. In Chinese, 女宿, meaning Girl , refers to an asterism consisting of μ Aquarii, ε Aquarii, 4 Aquarii, 5 Aquarii and 3 Aquarii. Consequently, the Chinese name for μ Aquarii itself is 女宿二