Abbreviation:

Mus

English name:

Fly

Coordinates

see Stellar data

Particulars:

• Double stars beta Mus, theta Mus
• Planetary Nebula NGC 5189
• Globular clusters NGC 4833, NGC 4372

General:

A small constellation in the cirumpolar regions of the south pole of the sky and a member of the Bayer constellation family. Musca was originally designed as a bee, Apis, by Bayer (in the sky atlas of 1801 by Johann Bode this constellation is also pictured as a bee). Its is not clear who changed ther designation (Halley ?).
North of Musca lies Crux, the Southern Cross. A part of the Coalsack Nebula extends from Crux into Musca.

Stars and other objects

Viewed by the naked eye, beta Mus appears as a blue-white 3rd mag star (spectraltype B2.5V). Using a telescope with an aperture of 100 mm reveals two close 4th mag stars.
The double theta Mus consists of a blue-white supergiant (B0Ia) of 5th mag with an 7th mag companion. This companion belong to a very interesting group of stars: it's an so-called Wolf-Rayet star (WC5). These very hot stars show broad emission lines and strong stellar winds (about 500 to 800 km/sec, sometimes even significantly higher). How the gas of the atmosphere is accelerated to reach such an high velocity is not yet known.
This double can be viewed with small telescopes.

Mythological Background:

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