Canis Majoris

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Canis Majoris was one of the original 48 constellations that were observed by Ptolemy. It is still included in the 88 constellations that are currently recognized by the International Astronomical Union. This constellation is referred to as one of the dogs that follows Orion in the night sky. The brightest star in the night sky, Sirius, is in this constellation. Canis Majoris contains 8 main stars and has another 32 with Bayer/Flamsteed designations.

Depending on the faintness of the stars, Canis Majoris, can resemble a dog facing above or below the ecliptic. There are many legends form ancient times that surround this constellation. The helical rising of its mains star, Sirius, announced the arrival of the worst heat of the summer. This led to naming these days the ”dog days” of summer since only the dogs were crazy enough to go out in that kind of heat. Therefore; Sirius was named the dog star and the constellation became known as the Big Dog. Usually, Canis Majoris is known as Orion’s hound, helping him to chase Lepus the Hare or Taurus the Bull.

When talking about Canis Majoris it is impossible to skip over a description of Sirius. Sirius is a binary system. The original discovery is credited to Alvan Clark, Jr. He was testing a new refractor at Dearborn Observatory when he found the white dwarf, Sirius B. Sirius A has a magnitude of -1.6 and Sirius B stands at 8.5. In order to see the B star you have to look into the evening sky(not night) and catch Sirius at its highest point. Using a mid-to-large telescope with a high power eyepiece, you will be able to discern the two stars.

Another star in the Canis Majoris constellation is Beta or Murzim. It is a variable magnitude blue-white giant. Murzim varies from 1.95 to 2.00 every six hours. It is a Beta Cephei star. It is in the final stages of using hydrogen as fuel and will soon begin to use helium to fuel itself. Next, you will be interested in Eta Canis Majoris, also known as Aludra. It shines fairly bright in the night sky because of its absolute magnitude. A blue supergiant, Aludra is many times brighter than the Sun. This star is much younger than our Sun, but is in the end stages of its life. It will turn supernova in the next few million years.

One last point of interest in the Canis Majoris constellation is VY Canis Majoris. This is a red hypergiant star. It is the largest known star and is also one of the most luminous. It is located about 5,000 light years from Earth. The estimated radius of the star is 1800 to 2100 times solar. IF it were plopped into the place of the Sun its size would take out into the orbit of Saturn.

Canis Majoris is a fascinating constellation and we have another great article about it here on Universe Today. Astronomy Cast offers a good episode about the 88 constellations.

Tagged as: Canis Majoris, Sirius