Constellation Chart

The Fly

Derivation

The origins of Musca are difficult to discern. Like its neighbour Crux, this region of the sky was originally included within the bounds of the large constellation Centaurus. Most sources suggest that Johann Bayer added the Fly to the heavens, though some hold Jacob Bartsch responsible. Whomever was responsible, they have left us with a faint star-group containing little of interest.

Stars

Musca lies almost centrally on the band of the Milky Way, and so presents a rich starfield when viewed through binoculars or a telescope. To the unaided eye, though, its stars are rather dim. The brightest, the blue Alpha Muscae, is only of magnitude +2.7, while the Beta star, which is also blue and lies within a few light years of Alpha, is slightly fainter at magnitude +3.0.

Nebula's In Musca

MyCn18

This image of MyCn18, a young planetary nebula located about 8,000 light-years away, reveals the true shape of MyCn18 to be an hourglass with an intricate pattern of "etchings" in its walls. This picture has been composed from three separate images taken in the light of ionized nitrogen (represented by red), hydrogen (green), and doubly-ionized oxygen (blue). The results are of great interest because they shed new light on the poorly understood ejection of stellar matter which accompanies the slow death of Sun-like stars. In previous ground-based images, MyCn18 appears to be a pair of large outer rings with a smaller central one, but the fine details cannot be seen.

According to one theory for the formation of planetary nebulae, the hourglass shape is produced by the expansion of a fast stellar wind within a slowly expanding cloud which is more dense near its equator than near its poles. What appears as a bright elliptical ring in the center, and at first sight might be mistaken for an equatorially dense region, is seen on closer inspection to be a potato shaped structure with a symmetry axis dramatically different from that of the larger hourglass. The hot star which has been thought to eject and illuminate the nebula, and therefore expected to lie at its center of symmetry, is clearly off center. Hence MyCn18, as revealed by Hubble, does not fulfill some crucial theoretical expectations.

Hubble has also revealed other features in MyCn18 which are completely new and unexpected. For example, there is a pair of intersecting elliptical rings in the central region which appear to be the rims of a smaller hourglass. There are the intricate patterns of the etchings on the hourglass walls. The arc-like etchings could be the remnants of discrete shells ejected from the star when it was younger (e.g. as seen in the Egg Nebula), flow instabilities, or could result from the action of a narrow beam of matter impinging on the hourglass walls. An unseen companion star and accompanying gravitational effects may well be necessary in order to explain the structure of MyCn18.

Other Objects In Musca

NGC 4372

NGC 4372 is a fairly large and somewhat faint globular cluster in Musca. In a small telescope it appears as a hazy patch of light that can be difficult if there is much light pollution. In an 8" telescope it is easy to observe and to resolve.

NGC 4833

NGC 4833 is a fairly bright (8th mag) globular cluster one degree north of delta Muscae.

NGC5189

Explanation: After a Sun-like star can no longer support fusion in its core, the center condenses into a white dwarf while the outer atmospheric layers are expelled into space and appear as a planetary nebula. This particular planetary nebula has a quite strange and chaotic structure. The inner part of this nebula contains an unusual expanding ring of gas that we see nearly edge-on. The exact mechanism that expels the planetary nebula gas is a current topic of astronomical speculation and research.

Planetary Destinations In Musca

HD 111232 (G8 V)

Parent Star: HD 111232 (G8 V) in the constellation of Musca is located at a distance of 94.58 Light Years from our Solar system. Co-ordinates of Right Ascension: 12 48 51.7543 & Declination: -68 25 30.544. The apparent Magnitude of the star is 7.61. The Inner Edge of Habitability Zone is 0.41 AU & the Outer Edge of Habitability Zone: 1.3 AU and the estimated stellar lifespan of the star is 21072 million years. Orbiting around HD 111232 is planet HD 111232 b the planet is believed to be a water cloud jovian and its exitence has been confirmed. The Planets Appearance is white water ice clouds. The planet orbits the star at Mean Orbital Distance of 1.97 AU and is outside of the habitability zone. The planet Orbits around the star every 1143 ± 14 Days and was discovered by MAYOR M. et al in 2003.