Canis Major is a constellation in the southern hemisphere and is in the in the Orion family of stars
Canis major was originally found by the Babylonians and the Chinese.
The myth for Canis is that Canis is a dog that is following Orion and is chasing a rabbit represented by the constellation Lepus. Canis represents Laepus, the fastest dog in the world, who caught anything that he pursued.Zeus gave Laelaps to Europa as a present, along with a javelin that could not miss. The gift proved to be an unfortunate one, as Europa herself was killed accidentally by her husband Cephalus, who was out hunting with the javelin.Cephalus took the dog to Thebes in Boeotia (a Greek province north of Athens) to hunt down a fox that was causing some trouble there. Like Laelaps, the fox was extremely fast and was destined never to be caught. Once the dog found the fox and started chasing it, the race did not appear to have an end in sight. Zeus himself finally ended it and turned both animals to stone. He placed the dog in the night sky as the constellation Canis Major.
Sirius, also known as the Dog Star, is the brightest star in the sky and the fifth nearest star system to the Sun. Sirius is a binary star with an apparent visual magnitude of -1.42. It is only 8.6 light years distance. The brighter component, Sirius A, is a white main sequence star and the companion, Sirius B, is a white dwarf that orbits the primary every 50 years.The distance between the two stars varies between 8.1 and 31.5 astronomical units. The companion is not visible to the naked eye. Sirius A belongs to the spectral class A1V, and the dwarf to DA2. Sirius A has twice the mass of the Sun and is 25 more luminous. Sirius B is almost equal to the Sun in mass (0.98 solar masses) and is one of the most massive white dwarfs known. Sirius A has an absolute visual magnitude of 1.42 and Sirius B, 11.18. The age of the star system is estimated to be between 200 and 300 million years. The name Sirius comes from the Greek Σείριος (Seirios), which means “scorching,” “glowing” or “searing.” In ancient times, the star rose just before sunrise during the hottest summer period, the so-called Dog Days. Greeks and Romans believed the star was somehow responsible for the summer heat.
Adhara is the second brightest star in Canis Major and the 24th brightest star in the night sky. Its name comes from the Arabic aðāra, which means “virgins.” It is a binary star that lies about 430 light years from Earth.The primary component belongs to the spectral class B2 and has an apparent magnitude of 1.5. It is one of the brightest known ultraviolet sources in the sky. The companion star has an apparent magnitude of 7.5 and is located 7.5’’ away from the primary.About 4.7 million years ago, Adhara was the brightest star in the sky. It was only 34 light years distant and had a magnitude of -3.99. No other star has ever been as bright since, nor is one expected to be in the next five million years.
Wezen is a yellow-white F-type supergiant approximately 1,800 light years distant. It has an apparent magnitude of 1.83. It is the third brightest star in Canis Major. Wezen can be found about 10 degrees southeast of Sirius. Its name is derived from the Arabic al-wazn“, meaning “the weight.” The star’s estimated age is 10 million years, which means that it will become a red supergiant within the next 100,000 years, and eventually a supernova.
Murzim (Al-Murzim, Mirzam) is a blue-white giant with brightness varying between magnitude 1.95 and 2.00. It is approximately 500 light years distant. The star’s name comes from the Arabic word for “the herald,” presumably referring to Murzim’s position in the sky. (The star rises before Sirius, i.e. it heralds it.)Murzim is classified as a Beta Cephei variable, a star that exhibits variations in brightness as a result of pulsations of its surface.
Aludra is an Alpha Cygni type variable star, with luminosity varying between magnitude 2.38 and 2.48. It is a blue supergiant, approximately 3,000 light years distant, and already approaching the final stages of its life. It is expected to become a supernova within the next few million years.The star’s name is derived from the Arabic al-‘aðrā, meaning “the virgin.” Along with Adhara, Wezen and Omicron-2 Canis Majoris, Aludra was one of the stars known as the Virgins.
Tau CMa is an eclipsing spectroscopic binary star about 3,200 light years from Earth. It is the brightest star of the open cluster NGC 2362 (Caldwell 64), which is why the cluster is sometimes called the Tau Canis Majoris Cluster.The star is an O-type blue supergiant classified as a Beta Lyrae type variable. Its brightness varies between magnitude 4.32 and 4.37 with a period of 1.28 days.
Muliphein is a blue-white B-type right giant, approximately 402 light years distant. It has an apparent visual magnitude of 4.11.