Mu Andromedae

Mu Andromedae (Mu And, μ Andromedae, μ And) is the Bayer designation for a star in the northern constellation of Andromeda. It has an apparent visual magnitude of 3.87,[2] making it readily visible to the naked eye. Based upon parallax measurements, it is approximately 130 light-years (40 parsecs) from Earth.[1] In the constellation, the star is situated about halfway between the bright star Mirach to the southwest and the Andromeda Galaxy (M31) to the northeast.[11]

The spectrum of this star matches a stellar classification of A5 V,[3] indicating that it is an A-type main sequence star. It has double the mass of the Sun and 2.4 times the Sun's radius.[7] The star is radiating about 21[7] times the luminosity of the Sun from its outer envelope at an effective temperature of 7,959 K,[8] giving it the characteristic white glow of an A-type star.[12] It is estimated to be about 600 million years old,[10] with a relatively high projected rotational velocity of 75 km/s.[9] Mu Andromedae has recently been found to be a binary system. The two stars orbit each other every 550.7 days.