Saturday, 27 June 2020

Astrognome A-Z of Constellations # 62 Pegasus


Pegasus the Flying Horse
The winged horse of Greek mythology, born from the blood of Medusa after she was slain by Perseus, who can be found nearby in the sky. The most famous feature is the great square outlined by 4 stars. Strangely and for some unknown reason the top left hand star of the square which used to be known as delta Pegasi has now been transferred to Andromeda where it has become alpha Andromedae.
The great square which covers a large area and contains surprisingly few naked eye stars, look at the square you will do well to see a dozen stars.
Alpha or Markab which means saddle is the bottom right hand star of the square its magnitude is 2.5 but is believed to be variable, it is a class A0 star with a temperature of 9,500’C and is 133 light years away.
Beta or Scheat which means shoulder is the top right hand star of the square it varies in brightness between magnitude 2.4-2.7. It is a red M2 class giant star with a temperature of 3,500’C. The star is 196 light years away.
Gamma or Algenib which means the wing or side is the bottom left hand star of the square with a magnitude of 2.8, lying 390 light years away. It is a B2 class star with a temperature of 20,000’ C
Epsilon or Enif which means the nose is 690 light years away and we see it as at magnitude 2.4 , its an orange K2 supergiant star with a temperature of 3,500’C.
Eta or Matar which means lucky star of rain has a magnitude of 2.9 lying 167 light years away. It is a G2 giant star with a temperature of 4,700’C.
For a large constellation Pegasus contains few nebulae or clusters, the only object that will interest us is M15 an outstandingly bright globular cluster at magnitude 6.2 which can easily be seen through binoculars. M15 at 12 billion years old it is one of the oldest known.
M15 is about 33,600 light years away and is about 175 light years in diameter and contains around 100,000 stars.







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