Andromeda III is a

dwarf spheroidal galaxy A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and as systems that are c ...

about 2.44 million

light-year A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by the International Astr ...

s away in the

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The first constellati ...

Andromeda. It is part of the

Local Group The Local Group is the galaxy group that includes the Milky Way, where Earth is located. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a " dumbbell" shape; the Milky Way ...

and is a

satellite galaxy A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and Luminosity, luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents ...

of the

Andromeda Galaxy The Andromeda Galaxy is a barred spiral galaxy and is the nearest major galaxy to the Milky Way. It was originally named the Andromeda Nebula and is cataloged as Messier 31, M31, and NGC 224. Andromeda has a Galaxy#Isophotal diameter, D25 isop ...

(M31). The galaxy was discovered by

Sidney van den Bergh Sidney Van den Bergh (born 20 May 1929) is a retired Dutch-Canadian astronomer. Van den Bergh showed an interest in science from an early age, learning to read with books on astronomy. In addition to being interested in astronomy, he also like ...

on photographic plates taken in 1970 and 1971. Observations of the dwarf galaxy using the WFPC2 in 2002 indicate that the bulk of the galaxy is around three billion years younger than the general population of

globular cluster A globular cluster is a spheroidal conglomeration of stars that is bound together by gravity, with a higher concentration of stars towards its center. It can contain anywhere from tens of thousands to many millions of member stars, all orbiting ...

s in our own galaxy. However, there are some older stars that are comparable in age to the

Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...

galactic clusters. There is no evidence for younger stars in this dwarf galaxy, suggesting no star formation is occurring. The dwarf galaxy is located at a distance of around from the center of M31. A total of 56

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes systematically with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are ...

s have been discovered in And III, including 51

RR Lyrae variable RR Lyrae variables are periodic variable stars, commonly found in globular clusters. They are used as standard candles to measure (extra) galactic distances, assisting with the cosmic distance ladder. This class is named after the prototype a ...

References

External links

SEDS: Dwarf Spheroidal Galaxy Andromeda III
{{DEFAULTSORT:Andromeda 03 Dwarf spheroidal galaxies Local Group Andromeda Subgroup Andromeda (constellation) 02121 ?

See also

References

External links