1) α Canis Majoris is actually a double star. The brighter star (Sirius A) we see is a white main sequence star while its companion (Sirius B) is a 8.4 magnitude white dwarf circling Sirius A every 50 years.
2) We get the phrase “dog days of summer” from the Egyptians and the Romans thanks to Sirius. During those times, Sirius and the Sun rose at the same time in the summer. These ancients believed the Dog Star caused all those hot summer days because the star added its heat to the Sun’s heat. Homer, Caesar, Cicero and even Virgil all wrote of Sirius as the cause of summer heat. Roman farmers even sacrificed fawn-colored dogs to appease the gods and avoid hot summers.
3) Sirius became the first star to have its velocity measure when, in 1868, Sir William Huggins, noticed a red shift in the spectrum of the star. His calculations were off by about five times, but at least he got the direction right.
4) Although the name Sirius derives from the Latin “Sirius,” the Latin term probably merely copied the Greek name “Seirios,” which means “glowing” or “Scorcher.”
5) Edmond Halley (yes, the Comet guy), comparing his measurements of Sirius to Ptolemy’s, in 1718 became the first astronomer to prove stars weren’t “fixed” and actually possess a proper motion.
