is a northern constellation
, named after the mythological winged horse Pegasus
. It is one of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy
(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.
Deep sky objects
History and mythology
Pegasus was born from the blood of Medusa
when she was slain by Perseus
Pegasus has an appearance resembling a grazing horse, with a large square area as its body. Due to the presence of the 4 brightest stars in the square, i.e. the 4 horses of Pegasus, this may be part of the origin of the myth of the Mares of Diomedes , one of The Twelve Labours of Heracles, together with another feature in the Zodiac sign of Aquarius, namely Aquarius itself, pouring out the waters.
The star formerly known as Delta Pegasi (labeled "Sirrah" in the map), one of the 4 stars in Pegasus' square, is now considered to be part of Andromeda, (α Andromedae) and is more usually called "Alpheratz." By moving the star, the square became a triangle attached to a stick body, thus resembling a wing. As a winged horse, Pegasus features in Greek mythology as its namesake, Pegasus.
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.
- H. A. Rey, The Stars — A New Way To See Them. Enlarged World-Wide Edition. Houghton Mifflin, Boston, 1997. ISBN 0-395-24830-2.
- Ian Ridpath and Wil Tirion (2007). Stars and Planets Guide, Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.