Andromeda III is a
dwarf spheroidal galaxy about 2.44 million
light-year
A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...
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 origins of the e ...
Andromeda. It is part of the
Local Group
The Local Group is the galaxy group that includes the Milky Way.
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 its satellites form ...
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 luminous host galaxy (also known as the primary galaxy). Satellite galaxies and their constituents are bound ...
of the
Andromeda Galaxy (M31). The galaxy was discovered by
Sidney van den Bergh
Sidney Van den Bergh, OC, FRS (born 20 May 1929 in Wassenaar) is a retired Dutch-Canadian astronomer.
He showed an interest in science from an early age, learning to read with books on astronomy. In addition to being interested in astronomy. ...
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 clusters in our own galaxy. However, there are some older stars that are comparable in age to the
Milky Way
The Milky Way is the galaxy that includes our Solar System, with the name describing the galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars that cannot be individually distinguished by the naked eye ...
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 with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...
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 and ...
s.[
]
See also
* List of Andromeda's satellite galaxies
The Andromeda Galaxy (M31) has satellite galaxies just like the Milky Way. Orbiting M31 are at least 13 dwarf galaxies: the brightest and largest is M110, which can be seen with a basic telescope. The second-brightest and closest one to M31 is ...
References
External links
SEDS: Dwarf Spheroidal Galaxy Andromeda III
{{DEFAULTSORT:Andromeda 03
Dwarf spheroidal galaxies
Local Group
Andromeda Subgroup
Andromeda (constellation)
02121
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