Beta Andromedae
Beta Andromedae, Latinized from β Andromedae, and officially named Mirach , is a prominent star in the northern constellation of Andromeda. It is northeast of the Great Square of Pegasus and is potentially visible to all observers north of latitude 54° S. It is commonly used by stargazers to find the Andromeda Galaxy. The galaxy NGC 404, also known as Mirach's Ghost, is seven arcminutes away from Mirach. This star has an average apparent visual magnitude of 2.05, making it the brightest star in the constellation. The luminosity varies slightly from magnitude +2.01 to +2.10. Based upon  parallax measurements, it is roughly from the Sun. Its apparent magnitude is reduced by 0.06 by extinction due to gas and dust along the line of sight. The star has a negligible radial velocity of 0.1 km/s, but with a relatively large proper motion, traversing the celestial sphere at ·yr. Properties. Beta Andromedae is a single red giant with a stellar classification of M0 III, and is currently on the asymptotic giant branch of its evolution. Since 1943 the spectrum of this star has been one of the stable anchor points by which other stars are classified. It is  suspected of being a semiregular variable star whose apparent visual magnitude varies from +2.01 to +2.10. At this stage of the star's evolution, the outer envelope has expanded to around 100 times the size of the Sun. It is radiating 1,995 times the luminosity of the Sun at an effective temperature of . Nomenclature. "Beta Andromedae" is the star's Bayer designation. It had the traditional name of "Mirach", and its variations, such as "Mirac", "Mirar", "Mirath", "Mirak", etc. (the name is spelled "Merach" in Burritt's "The Geography of the Heavens"), which come from the star's description in  the "Alfonsine Tables" of 1521 as "super mizar". Here, "mirat" is a corruption of the Arabic مئزر "mīzar" "girdle", which appeared in a Latin translation of the "Almagest". This word refers to Mirach's position at the left hip of the princess Andromeda. In 2016, the International Astronomical Union organized a Working Group on Star Names (WGSN) to catalog and standardize proper names for stars. The WGSN's first bulletin of July 2016 included a table of the first two batches of names approved by the WGSN; which included "Mirach" for this star. Mirach is listed in the Babylonian MUL.APIN  as KA.MUSH.I.KU.E, meaning "the Deleter" (the alternative star is α Cas). Medieval astronomers writing in Arabic called β Andromedae "Janb al-Musalsalah" (); it was part of the 28th "manzil" (Arabian lunar mansion) "Baṭn al-Ḥūt", the Belly of the Fish, or "Qalb al-Ḥūt", the Heart of the Fish. The star has also been called "Cingulum" and "Ventrale". This "al-Ḥūt" was an indigenous Arabic constellation, not the Western "Northern Fish" part of the constellation Pisces. These names are not from the Arabic "marāqq", loins, because it was never called "al-Marāqq" in Arabian astronomy. "Al Rishā, the Cord (of  the well-bucket), on al-Sūfī's star map. It is origin of the proper name Alrescha"' for Alpha Piscium. In Chinese, (), meaning "Legs", refers to an asterism consisting of β Andromedae, η Andromedae, 65 Piscium, ζ Andromedae, ε Andromedae, δ Andromedae, π Andromedae, ν Andromedae, μ Andromedae, σ Piscium, τ Piscium, 91 Piscium, υ Piscium, φ Piscium, χ Piscium and ψ Piscium. Consequently, the Chinese name for β Andromedae itself is (, ). The people of Micronesia named this star "Kyyw", meaning "The Porpoise", and this was used as one of the names of the months in Micronesia. Beta Andromedae Beta