Musca facts for kids

Kids Encyclopedia Facts

This page is about the southern constellation. For the fly genus, see Musca (fly). For other uses, see Musca (disambiguation).

Quick facts for kids
Musca
Constellation
List of stars in Musca
Abbreviation	Mus
Genitive	Muscae
Pronunciation	genitive
Symbolism	the Fly
Right ascension	11^h 19.3^m–13^h 51.1^m
Declination	−64.64°–−75.68°
Quadrant	SQ3
Area	138 sq. deg. (77th)
Main stars	6
Bayer/Flamsteed stars	13
Stars brighter than 3.00^m	1
Stars within 10.00 pc (32.62 ly)	1
Brightest star	α Mus (2.69^m)
Messier objects	0
Bordering constellations	Apus Carina Centaurus Chamaeleon Circinus Crux
Visible at latitudes between +10° and −90°. Best visible at 21:00 (9 p.m.) during the month of May.

Musca (Latin for 'the fly') is a small but fascinating constellation found deep in the southern sky. It's one of the 12 constellations first mapped by Petrus Plancius. He used observations from explorers Pieter Dirkszoon Keyser and Frederick de Houtman. Musca first appeared on a special map of the sky called a celestial globe in 1597 or 1598.

This constellation was also known as Apis (Latin for 'the bee') for about 200 years. Most people in the Northern Hemisphere cannot see Musca because it stays below the horizon. Many of its brightest stars are part of a large group called the Scorpius–Centaurus association. These are hot, blue-white stars that seem to have formed together.

Musca is home to some amazing celestial objects. These include stars with planets orbiting them, called exoplanets. It also has special stars that change brightness, known as Cepheid variables. One star system, Theta Muscae, even contains a very hot and massive star called a Wolf–Rayet star.

Discovering Musca: A Sky Story
- How Musca Got Its Name
Musca's Place in the Sky
Amazing Stars in Musca
Cosmic Wonders: Deep-Sky Objects
- Beautiful Nebulae
- Star Clusters to Explore
See also

Discovering Musca: A Sky Story

Musca (then called Apis, the Bee) is shown in the upper right corner of this old sky map from 1603.

Musca was one of 12 constellations created by the astronomer Petrus Plancius. He used notes from Dutch explorers Pieter Dirkszoon Keyser and Frederick de Houtman. These explorers sailed on the first Dutch trading trip to the East Indies. De Houtman listed Musca in his star catalog in 1598. He called it De Vlieghe, which means "The Fly" in Dutch.

The explorers imagined four stars forming the fly. Beta Muscae was the head, Gamma was the body, and Alpha and Delta were the wings. This constellation first appeared on a celestial globe in 1598. A celestial globe is like a map of the stars on a sphere.

How Musca Got Its Name

The first time Musca appeared in a star atlas was in 1603. This atlas was called Uranometria by German mapmaker Johann Bayer. However, Bayer called it Apis, meaning "the Bee." This name stuck for the next two centuries. An old globe from 1603 even showed the nearby constellation Chamaeleon trying to catch the insect with its tongue!

Later, in 1756, French astronomer Nicolas Louis de Lacaille called it la Mouche, which is French for "the Fly." He later gave it the Latin name Musca Australis, meaning "the Southern Fly." He added "Australis" to avoid confusion with another constellation, Apus, and a now-unused constellation called Musca Borealis (the Northern Fly). Today, we simply call it Musca. It is the only official constellation that represents an insect.

The Kalapalo people in Brazil saw Alpha and Beta Muscae as "Ornate Hawk-Eagle's double flutes." The Wardaman people in Australia saw Musca's main stars as a ceremonial boomerang. They also saw Alpha and Beta as a ceremonial headband. Gamma and Delta represented two armbands.

Musca's Place in the Sky

Musca is surrounded by other constellations. To its north is Crux, to the west is Carina, and to the south is Chamaeleon. Apus and Circinus are to its east, and Centaurus is to the northeast.

Musca covers 138 square degrees of the night sky. This makes it the 77th largest of the 88 constellations. The International Astronomical Union (IAU) officially uses "Mus" as its three-letter abbreviation. The entire constellation can be seen by anyone living south of 14°N latitude.

Amazing Stars in Musca

Musca as it appears to the unaided eye.

Astronomers have charted many stars in Musca. There are 62 stars brighter than magnitude 6.5 in this constellation. The brightest stars in Musca form a shape that looks a bit like a bowl with a handle.

Brightest Stars and Their Secrets

Alpha Muscae is the brightest star in Musca. It shines with an apparent magnitude of 2.7. This blue-white star is about 310 light-years away. It is much bigger and brighter than our Sun. Alpha Muscae is a special type of star called a Beta Cephei variable. It pulsates, meaning it changes its brightness slightly every 2.2 hours.
Gamma Muscae marks the fly's tail. It is a blue-white star that also changes brightness. It varies between magnitudes 3.84 and 3.86 over 2.7 days. It is about five times more massive than the Sun.
Beta Muscae is a binary star system. This means it has two stars orbiting each other. Both are blue-white stars, and they complete an orbit every 194 years. They are about 341 light-years away.
Delta Muscae and Epsilon Muscae mark the fly's wings. Delta is an orange giant star about 91 light-years away. Epsilon is a red giant star that changes brightness over about 40 days. It has grown to be 130 times larger than the Sun!
Lambda Muscae is the third-brightest star in the constellation. It is a white star about 128 light-years from Earth.

Special Stars: Variables and More

R Muscae and S Muscae are both Cepheid variables. These are yellow-white supergiant stars that brighten and dim in a very regular pattern. This pattern helps astronomers measure distances in space. R Muscae changes brightness over 7.5 days, and S Muscae over 9.66 days. S Muscae is also a binary star with a blue-white companion.
Theta Muscae is a system of three very bright stars. One of them is a Wolf–Rayet star, which is a very hot and massive star. These stars are thought to be about 7,500 light-years away.
TU Muscae is a binary star system where two hot, blue stars are so close they actually touch each other! They are called an overcontact binary. As they orbit, they eclipse each other, causing their combined light to change.
GQ Muscae is a binary system with a white dwarf and a small star. A white dwarf is the leftover core of a star like our Sun. In 1983, GQ Muscae had a sudden outburst, becoming much brighter. This event is called a nova. It was the first nova where X-rays were detected.
GRS 1124-683 is another binary system. It has an orange star orbiting a black hole. A black hole is a region in space where gravity is so strong that nothing, not even light, can escape.

Stars with Planets: Exoplanets!

Astronomers have found planets orbiting stars in Musca! These are called exoplanets.

HD 111232 is a yellow star similar to our Sun. It has a planet, HD 111232 b, that is almost seven times bigger than Jupiter. This planet takes about 1143 days to orbit its star.
HD 112410 is a yellow giant star. It has a companion that is about nine times the mass of Jupiter. This companion orbits the star every 124.6 days.
HD 100546 is a young, blue-white star. It is surrounded by a disk of dust and gas. Scientists believe a large planet, or even more than one, might be forming within this disk! This star is about 320 light-years away.
LP 145-141 is a white dwarf star, one of the closest to our Solar System. It is a good place to look for other Jupiter-like planets.

Cosmic Wonders: Deep-Sky Objects

Musca also contains many beautiful and mysterious objects beyond individual stars.

Beautiful Nebulae

NGC 5189 is a stunning planetary nebula. It looks like a twisted ribbon of gas. A planetary nebula is a cloud of glowing gas and dust shed by a dying star. This one is about 1750 light-years away.
The Engraved Hourglass Nebula (MyCn 18) is another planetary nebula. It has a unique hourglass shape. It is located about 8000 light-years from Earth.
The Coalsack Nebula is a famous dark nebula. A dark nebula is a cloud of dust and gas that blocks the light from stars behind it, making it look like a dark patch in the sky. It extends into Musca from the neighboring constellation Crux.
The Dark Doodad Nebula is another dark nebula. It looks like a dark, L-shaped river flowing through a bright field of stars.

Star Clusters to Explore

NGC 4463 is an open cluster. This is a group of young stars that formed together and are loosely bound by gravity. It is about 3400 light-years away.
NGC 4833 is an old globular cluster. Globular clusters are dense, spherical groups of hundreds of thousands of very old stars. This cluster is about 21,200 light-years away.
NGC 4372 is another globular cluster. It is fainter but covers a larger area in the sky. This cluster is very old, making it one of the oldest in the Milky Way galaxy. It is about 18,900 light-years from Earth.