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Pegasus (constellation)
Encyclopedia
Pegasus is a constellation
in the northern sky, named after the winged horse Pegasus
in Greek mythology
. It was one of the 48 constellations listed by the 2nd century astronomer
Ptolemy
, and remains one of the 88 modern constellations.
(Markab), β Peg
, and γ Peg
, together with α Andromedae
(Alpheratz or Sirrah) form the large asterism
known as the Square of Pegasus.
51 Pegasi
, a star in this constellation, is the first Sun-like star known to have an extrasolar planet
.
IK Pegasi is the nearest supernova
candidate.
Spectroscopic analysis of HD 209458 b
, an extrasolar planet
in this constellation has provided the first evidence of atmospheric water vapor
beyond the solar system, while extrasolar planets orbiting the star HR 8799
also in Pegasus are the first to be directly imaged.
Pegasus is dominated by an asterism
in the shape of a rough square, although one of the stars, Delta Pegasi
or Sirrah, is now officially considered to be part of Andromeda
, (α Andromedae) and is more usually called "Alpheratz".
H.A. Rey has suggested an alternative way to connect the stars into the shape of a winged horse. The body of the horse consists of a quadrilateral formed by the stars α Peg
, β Peg
, γ Peg
, and α And
. The front legs of the winged horse are formed by two crooked lines of stars, one leading from η Peg
to κ Peg and the other from μ Peg
to 1 Pegasi. Another crooked line of stars from α Peg
via θ Peg
to ε Peg forms the neck and head; ε is the snout.
and USS Pegasus (PHM-1)
are United States
navy ships named after the constellation.
Constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....
in the northern sky, named after the winged horse Pegasus
Pegasus
Pegasus is one of the best known fantastical as well as mythological creatures in Greek mythology. He is a winged divine horse, usually white in color. He was sired by Poseidon, in his role as horse-god, and foaled by the Gorgon Medusa. He was the brother of Chrysaor, born at a single birthing...
in Greek mythology
Greek mythology
Greek mythology is the body of myths and legends belonging to the ancient Greeks, concerning their gods and heroes, the nature of the world, and the origins and significance of their own cult and ritual practices. They were a part of religion in ancient Greece...
. It was one of the 48 constellations listed by the 2nd century astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
Ptolemy
Ptolemy
Claudius Ptolemy , was a Roman citizen of Egypt who wrote in Greek. He was a mathematician, astronomer, geographer, astrologer, and poet of a single epigram in the Greek Anthology. He lived in Egypt under Roman rule, and is believed to have been born in the town of Ptolemais Hermiou in the...
, and remains one of the 88 modern constellations.
Stars
α PegAlpha Pegasi
Alpha Pegasi is the third brightest star in the constellation Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. It has the traditional name Markab .Markab is a relatively average star nearing the end of its stellar evolution on the main sequence...
(Markab), β Peg
Beta Pegasi
Beta Pegasi is a star in the constellation Pegasus. Its traditional name is Scheat, a name that has also been used for Delta Aquarii....
, and γ Peg
Gamma Pegasi
Gamma Pegasi is a star in the constellation of Pegasus. It also has the traditional name Algenib; confusingly however, this name is also used for Alpha Persei....
, together with α Andromedae
Alpha Andromedae
Alpha Andromedae , which has the traditional names Alpheratz and Sirrah , is the brightest star in the constellation of Andromeda. Located immediately northeast of the constellation of Pegasus, it is the northeastern star of the Great Square of Pegasus...
(Alpheratz or Sirrah) form the large asterism
Asterism (astronomy)
In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...
known as the Square of Pegasus.
51 Pegasi
51 Pegasi
51 Pegasi is a Sun-like star located 15.6 parsecs from Earth in the constellation Pegasus...
, a star in this constellation, is the first Sun-like star known to have an extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
.
IK Pegasi is the nearest supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
candidate.
Spectroscopic analysis of HD 209458 b
HD 209458 b
HD 209458 b is an extrasolar planet that orbits the Solar analog star HD 209458 in the constellation Pegasus, some 150 light-years from Earth's solar system, with evidence of water vapor....
, an extrasolar planet
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
in this constellation has provided the first evidence of atmospheric water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
beyond the solar system, while extrasolar planets orbiting the star HR 8799
HR 8799
HR 8799 is a young main sequence star located 129 light years away from Earth in the constellation of Pegasus, with roughly 1.5 times the Sun's mass and 4.9 times its luminosity. It is part of a system that also contains a debris disk and at least four massive planets...
also in Pegasus are the first to be directly imaged.
Named stars
| Bayer designation Bayer designation A Bayer designation is a stellar designation in which a specific star is identified by a Greek letter, followed by the genitive form of its parent constellation's Latin name... |
Name | Origin | Meaning |
|---|---|---|---|
| α | Markab Alpha Pegasi Alpha Pegasi is the third brightest star in the constellation Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. It has the traditional name Markab .Markab is a relatively average star nearing the end of its stellar evolution on the main sequence... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
the saddle of the horse |
| β | Scheat Beta Pegasi Beta Pegasi is a star in the constellation Pegasus. Its traditional name is Scheat, a name that has also been used for Delta Aquarii.... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
the leg |
| γ | Algenib Gamma Pegasi Gamma Pegasi is a star in the constellation of Pegasus. It also has the traditional name Algenib; confusingly however, this name is also used for Alpha Persei.... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
the flank |
| ε | Enif | Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
nose |
| ζ | Homam Zeta Pegasi Zeta Pegasi is a star in the constellation Pegasus. It has the traditional name, Homam .... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
man of high spirit |
| η | Matar Eta Pegasi Eta Pegasi is a star in the constellation Pegasus. It has the traditional name Matar .Eta Pegasi is of spectral class G2II-III and has apparent magnitude +3.1. It is approximately 215 light years from Earth. It has a close companion of class F0V... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
lucky star of rain |
| θ | Baham Theta Pegasi Theta Pegasi is a star in the constellation Pegasus. It has the traditional name Baham .In Chinese, , meaning Rooftop, refers to an asterism consisting of θ Pegasi, α Aquarii and ε Pegasi. Consequently, θ Pegasi itself is known as Theta Pegasi is of spectral class A2 and has apparent magnitude... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
the livestocks |
| μ | Sadalbari Mu Pegasi Mu Pegasi is a star in the constellation Pegasus. It has the traditional name Sadalbari .It has spectral class M2 and is of apparent magnitude 3.5.... |
Arabic Arabic language Arabic is a name applied to the descendants of the Classical Arabic language of the 6th century AD, used most prominently in the Quran, the Islamic Holy Book... |
luck star of the splendid one |
Deep sky objects
- M15Messier 15Messier 15 or M15 is a globular cluster in the constellation Pegasus. It was discovered by Jean-Dominique Maraldi in 1746 and included in Charles Messier's catalogue of comet-like objects in 1764...
- a globular clusterGlobular clusterA globular cluster is a spherical collection of stars that orbits a galactic core as a satellite. Globular clusters are very tightly bound by gravity, which gives them their spherical shapes and relatively high stellar densities toward their centers. The name of this category of star cluster is...
near the nose (ε Peg) of Pegasus. - NGC 7742NGC 7742NGC 7742 is a face-on unbarred spiral galaxy in the constellation Pegasus.The galaxy is unusual in that it contains a ring but no bar. Typically, bars are needed to produce a ring structure. The bars' gravitational forces move gas to the ends of the bars, where it forms into the rings seen in...
- a Type 2 Seyfert galaxySeyfert galaxySeyfert galaxies are a class of galaxies with nuclei that produce spectral line emission from highly ionized gas, named after Carl Keenan Seyfert, the astronomer who first identified the class in 1943...
.
History
The Babylonian constellation IKU (field) had four stars of which three were later part of the Greek constellation Hippos (Pegasus).Visualizations
Asterism (astronomy)
In astronomy, an asterism is a pattern of stars recognized on Earth's night sky. It may form part of an official constellation, or be composed of stars from more than one. Like constellations, asterisms are in most cases composed of stars which, while they are visible in the same general direction,...
in the shape of a rough square, although one of the stars, Delta Pegasi
Alpha Andromedae
Alpha Andromedae , which has the traditional names Alpheratz and Sirrah , is the brightest star in the constellation of Andromeda. Located immediately northeast of the constellation of Pegasus, it is the northeastern star of the Great Square of Pegasus...
or Sirrah, is now officially considered to be part of Andromeda
Andromeda (constellation)
Andromeda is a constellation in the northern sky. It is named after Andromeda, the princess in the Greek legend of Perseus who was chained to a rock to be eaten by the sea monster Cetus...
, (α Andromedae) and is more usually called "Alpheratz".
H.A. Rey has suggested an alternative way to connect the stars into the shape of a winged horse. The body of the horse consists of a quadrilateral formed by the stars α Peg
Alpha Pegasi
Alpha Pegasi is the third brightest star in the constellation Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. It has the traditional name Markab .Markab is a relatively average star nearing the end of its stellar evolution on the main sequence...
, β Peg
Beta Pegasi
Beta Pegasi is a star in the constellation Pegasus. Its traditional name is Scheat, a name that has also been used for Delta Aquarii....
, γ Peg
Gamma Pegasi
Gamma Pegasi is a star in the constellation of Pegasus. It also has the traditional name Algenib; confusingly however, this name is also used for Alpha Persei....
, and α And
Alpha Andromedae
Alpha Andromedae , which has the traditional names Alpheratz and Sirrah , is the brightest star in the constellation of Andromeda. Located immediately northeast of the constellation of Pegasus, it is the northeastern star of the Great Square of Pegasus...
. The front legs of the winged horse are formed by two crooked lines of stars, one leading from η Peg
Eta Pegasi
Eta Pegasi is a star in the constellation Pegasus. It has the traditional name Matar .Eta Pegasi is of spectral class G2II-III and has apparent magnitude +3.1. It is approximately 215 light years from Earth. It has a close companion of class F0V...
to κ Peg and the other from μ Peg
Mu Pegasi
Mu Pegasi is a star in the constellation Pegasus. It has the traditional name Sadalbari .It has spectral class M2 and is of apparent magnitude 3.5....
to 1 Pegasi. Another crooked line of stars from α Peg
Alpha Pegasi
Alpha Pegasi is the third brightest star in the constellation Pegasus and one of the four stars in the asterism known as the Great Square of Pegasus. It has the traditional name Markab .Markab is a relatively average star nearing the end of its stellar evolution on the main sequence...
via θ Peg
Theta Pegasi
Theta Pegasi is a star in the constellation Pegasus. It has the traditional name Baham .In Chinese, , meaning Rooftop, refers to an asterism consisting of θ Pegasi, α Aquarii and ε Pegasi. Consequently, θ Pegasi itself is known as Theta Pegasi is of spectral class A2 and has apparent magnitude...
to ε Peg forms the neck and head; ε is the snout.
Namesakes
USS Pegasus (AK-48)USS Pegasus (AK-48)
USS Pegasus was built in 1939 as SS Rita Maersk by Helsingør Jernskibs og Maskinbyggeri A/A, Helsingør, Denmark. Following the outbreak of World War II in Europe, she sailed to the United States where she operated under charter from the Maritime Commission as Rita Maersk and later as Larwin...
and USS Pegasus (PHM-1)
USS Pegasus (PHM-1)
USS Pegasus was the lead ship of her class of hydrofoils operated by the United States Navy. Pegasus class vessels were designed for high speed and mobility, and carried a powerful armament....
are United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
navy ships named after the constellation.