The Pegasus Dwarf Irregular Galaxy (also known as Peg DIG or the Pegasus Dwarf) is a

dwarf Dwarf or dwarves may refer to: Common uses *Dwarf (folklore), a being from Germanic mythology and folklore * Dwarf, a person or animal with dwarfism Arts, entertainment, and media Fictional entities * Dwarf (''Dungeons & Dragons''), a humanoid ...

irregular galaxy An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearanc ...

in the direction of 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 ...

Pegasus Pegasus ( grc-gre, Πήγασος, Pḗgasos; la, Pegasus, Pegasos) is one of the best known creatures in Greek mythology. He is a winged divine stallion usually depicted as pure white in color. He was sired by Poseidon, in his role as hor ...

. It was discovered by A. G. Wilson in the 1950s. The Pegasus Dwarf is a companion of the

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...

in 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 ...

General information

In 1975 Tully & Fisher determined that it was part of the Local Group. The

metallicity In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a ...

and the related distance estimate has been subject to discussions in the scientific literature, with varying results; however, recently, by use of the

tip of the red-giant branch Tip of the red-giant branch (TRGB) is a primary distance indicator used in astronomy. It uses the luminosity of the brightest red-giant-branch stars in a galaxy as a standard candle to gauge the distance to that galaxy. It has been used in conjun ...

, a distance within 10% error was achieved in 2000 and then improved to 3% in 2005.

In popular culture

The

science fiction Science fiction (sometimes shortened to Sci-Fi or SF) is a genre of speculative fiction which typically deals with imaginative and futuristic concepts such as advanced science and technology, space exploration, time travel, parallel unive ...

television series ''

Stargate Atlantis ''Stargate Atlantis'' (usually stylized in all caps and often abbreviated ''SGA'') is an adventure and military science fiction television series and part of MGM's ''Stargate'' franchise. The show was created by Brad Wright and Robert C. Cooper ...

'' takes place in the "Pegasus galaxy" and has shown images of an irregular galaxy. However, the franchise has not explicitly stated if it is the Irregular,

Spheroidal A spheroid, also known as an ellipsoid of revolution or rotational ellipsoid, is a quadric surface obtained by rotating an ellipse about one of its principal axes; in other words, an ellipsoid with two equal semi-diameters. A spheroid has circ ...

, or an entirely fictional location." The Return" (''

'')

Notes

NED gives the galaxy classification as both dIrr and dSph, which means that it is a transitory between dwarf irregular and dwarf spheroidal. It is noted as transitory in Cole et al. 1999.

References

External links

* {{Sky, 23, 28, 36.2, +, 14, 44, 35, 3000000 Dwarf irregular galaxies Local Group Andromeda Subgroup Pegasus (constellation) 12613 71538

General information

In popular culture

See also

Notes

References

External links