Brian Jones: Aries
If you look into the south-eastern sky during November evenings you should make out Aries, this month’s small but well-defined constellation. Aries can be found a little over half way up from the south-eastern horizon towards the overhead point and, although not particularly prominent, the bent line of three stars that form the head of the Ram lie in an otherwise isolated area of sky, and you should have little trouble picking them out. Once you’ve located this trio, binoculars will help you to pick out the fainter members of the constellation in the area of sky a little to the east of these.
The legend behind this constellation is intriguing, Aries being associated with the legend of Jason and his quest to seek out the Golden Fleece. The marriage of King Athamas and his wife Nephele wasn’t a happy one, and Athamas decided to turn his attentions towards Ino, daughter of King Cadmus of Thebes. However, Ino turned out to be a rather wicked stepmother, taking a disliking to her two step-children Phrixus and Helle. She hatched a plot to have them killed which, naturally, prompted the children to try and escape. This they duly did, with the help of their mother Nephele, on a magical winged ram with a golden fleece. Unfortunately, during the flight Helle was frightened by the experience and fell off the ram, plunging to her death in the channel between Europe and Asia, the Dardanelles (which was named the Hellespont by the Greeks in her memory). Her brother Phrixus, however, survived and eventually landed safely in Colchis. Phrixus sacrificed the ram to Zeus (perhaps displaying a certain amount of ingratitude towards the poor animal), who promptly placed it amongst the stars where we can see it to this day. King Aeetes of Colchis kept the Golden Fleece, which was eventually sought out by Jason and the Argonauts.
Shining from a distance of just under 80 light years, the giant star Hamal is the brightest star in Aries and is named, appropriately enough, after the Arabic for Head of the Sheep. Sheratan is somewhat closer, its light having taken only around 50 years to reach us. This star derives its name from the Arabic for ‘two of something’, possibly alluding to the two horns of the Ram. The name Sheratan was originally jointly applied to this star and to nearby Mesarthim.
Mesarthim is an example of what astronomers refer to as an optical double star, both components of which can be resolved through a small telescope. However, Mesarthim only appears to be double because the two stars we see happen to lie in more or less the same line of sight as seen from Earth. In fact, these two stars lie at distances of 148 and 172 light years and only appear to be close to each other because of the line of sight effect.
There is a double star in Aries which can be resolved, with patience and a really clear sky, in a pair of steadily-held binoculars, although a magnification of at least 10x is needed. Shining from a distance of just over 130 light years, Lambda lies a little to the west of Hamal. The fact that Lambda is a double was first noted in the 18th century by the Moravian astronomer Christian Mayer. Unlike Mesarthim, however, Lambda is a true binary star, and the two components we see are actually orbiting each other.
Why not brave the chilly evenings and take up the challenge to resolve the two components of Lambda? Although small, the constellation of Aries is worth seeking out, so get out there and check out what the celestial ram has to offer! Happy stargazing!