Musca

Musca (Latin: fly) is a small constellation in the deep southern sky. It was one of twelve constellations created by Petrus Plancius from the observations of Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on a 35-cm (14 in) diameter celestial globe published in 1597 (or 1598) in Amsterdam by Plancius and Jodocus Hondius. The first depiction of this constellation in a celestial atlas was in Johann Bayer's Uranometria of 1603. It was also known as Apis (Latin: bee) for two hundred years. Musca remains below the horizon for most Northern Hemisphere observers. Many of the constellation's brighter stars are members of the Scorpius–Centaurus Association, a loose group of hot blue-white stars that appear to share a common origin and motion across the Milky Way. These include Alpha, Beta, Gamma, Zeta2 and (likely) Eta Muscae, as well as HD 100546, a blue-white Herbig Ae/Be star that is surrounded by a complex debris disk containing a large planet or brown dwarf and possible protoplanet. Two further star systems have been found to have planets. The constellation also contains two Cepheid variables visible to the naked eye. Theta Muscae is a triple star system, the brightest member of which is a Wolf–Rayet star. ... Musca is bordered by Crux to the north, Carina to the west, Chamaeleon to the south, Apus and Circinus to the east and Centaurus to the northeast. ... Stars. The pattern of the brightest stars resembles that of Ursa Minor, in that the stars form a pattern reminiscent of a bowl with a handle. Lying south-southeast of Acrux in neighbouring Crux is Alpha Muscae. It is the brightest star in the constellation with an apparent magnitude of 2.7. The star is a Beta Cephei variable with about 4.7 times the Sun's diameter, and pulsates every 2.2 hours, varying by 1% in brightness. ... Marking the fly's tail is Gamma Muscae, a blue-white star of spectral type B5V that varies between magnitudes 3.84 and 3.86 over a period of 2.7 days. It is a variable of a different type, classed as a Slowly pulsating B star, a type of variable. ... Beta Muscae is a binary star system around 341 light-years distant that is composed of two blue-white main sequence stars of spectral types B2V and B3V that orbit each other every 194 years. ... Delta and Epsilon mark the fly's left wing and right wing respectively.[16] With an apparent magnitude of 3.62, Delta is an orange giant of spectral type K2III located around 91 light-years away. Epsilon Muscae is a red giant of spectral type M5III and semiregular variable that ranges between magnitudes 3.99 and 4.31 over approximately 40 days. ... Deep-sky objects. Located on the border with Circinus is the unusual planetary nebula NGC 5189, estimated to be around 1750 light-years away from Earth. ... Located 2.4° east of Eta Muscae is the magnitude-12.9 Engraved Hourglass Nebula (MyCn 18), which lies about 8000 light-years distant from Earth. To Eta's west lies IC 4191, a compact bluish planetary nebula of magnitude 10.6, thought to lie around 10,750 light-years away from Earth. West of Epsilon Muscae is NGC 4071, a large, diffuse planetary nebula of magnitude 12.7 with a magnitude 12 central star, thought to lie around 4000 light-years away from Earth. The Coalsack Nebula is a dark nebula located mainly in neighbouring Crux that intrudes into Musca. NGC 4463 is an open cluster located on its southwestern border. Around five light-years across, it is located around 3400 light-years away. The comparatively old globular cluster NGC 4833 near Delta Muscae ... is 21,200 light-years distant and somewhat obscured by dust clouds near the galactic plane. The globular cluster NGC 4372 near Gamma Muscae is fainter and likewise partially obscured by dust, but spans more arc minutes. It is 18,900 light-years away from Earth and 23,000 light-years distant from the centre of the Milky Way. Its extremely low metallicity indicates it is very old—one of the oldest clusters in the Milky Way. Extending south from it is the Dark Doodad Nebula, resembling a dark L-shaped river through a bright field of stars. [Musca. Wikipedia]