Canis Minor the Lesser Dog – winter sky
In mythology it is
the smaller of the dogs that follows Orion the Hunter.
It has only one
bright star alpha or Procyon which means ‘Before the Dog’, this
is because it rises before Sirius. Procyon is the 8th
brightest star in the sky with a magnitude of 0.3. It is close to the
Earth being only 11.5 light years away. It is an F5 class star
meaning its slightly hotter than our Sun.
Procyon forms a very
prominent and large triangle with Sirius in Canis Major and
Betelgeuse in Orion.
By a remarkable
coincidence both of the dog stars are accompanied by white dwarfs.
The pup orbiting Sirius was discovered by Alvan Clark in 1862 when he
was testing a new telescope. The white dwarf orbiting Procyon was
discovered in 1896 at the Lick observatory using the 36 inch
refractor.
White dwarfs are the
remains of a star that has used up all its hydrogen fuel and what
remains is mostly helium, this makes them super dense objects with a
tea spoon weighing many tons.
The only other
notable star is beta or Gomeisa which means the ‘Bleary Eyed One’
It is of magnitude 2.9 and is 160 light years away, its a B8 class
star which means it is hotter than the sun.
Just above beta is
the faint star gamma which has a magnitude of 4.3 and is a K3 giant
class star which is cooler than our Sun, gamma is 320 light years
distant.
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