Aries the Ram - Northern Hemisphere
A constellation that
dates back to ancient times, in legend Aries represented the Ram
whose golden fleece was sought by Jason and the Argonauts. Despite
not being a very bright constellation it has assumed great importance
in astronomy, because around 2,000 years ago it contained the point
where the Sun passed from south to north across the celestial equator
each year. This point, the vernal equinox marked the start of spring
in the northern hemisphere.
This point is known
as the first point of Aries. However because of the slight wobble of
the Earth which is called precession this point has now moved into
the neighbouring constellation of Pisces. Having said that we still
call it the First Point of Aries.
The brightest star,
alpha is called Hamal which means ‘The Head of the Sheep’,it
shines at magnitude 2.0 the same brightness as the North Star. Hamal
lies 66 light years away and is a K1 giant with a surface temperature
of 4,200’C compared to 5,800’C of the Sun.
The next brightest
star is beta which is called Sheratan meaning ‘The Sign’, and is
60 light years away it has a magnitude of 2.7. Sheratan is an A5
class star with a temperature of 8,700’C much hotter than the Sun.
A line drawn from
Hamal and to the left and upwards slightly will reach the third
brightest star in Aries. This is 41 Arietis. I know I have said that
the brightest 24 stars of each constellation have a Greek letter
allocated to them. The first Astronomer Royal John Flamsteed
(1646-1719) undertook a survey of the night sky and gave every naked
eye star in a constellation a number, evens stars which have a Greek
letter.
41 Ariets has a
magnitude of 3.6 and is a B9 class star hotter than our Sun and is
166 light years distant. The star does not have a Greek letter
because it was originally part of a now defunct small constellation
called Musca Borealis the Northern Fly.
Just below beta you
will find gamma or Mesarthim the meaning is unknown, its magnitude is
3.9 and is 164 light years away Mesarthim is a B class star much
hotter than the Sun. The star used to be called ‘The First Star of
Aries’ as it was the closest visible star to the vernal equinox.
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