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Facts on the Star Sirius

The brightest star in the sky, Sirius is also commonly known as the Dog Star. Because of its visibility, it is the most well-known of stars, with many references found throughout history and in all cultures. Actually a binary star system (two stars revolving around each other), Sirius can be seen from almost all inhabited regions of Earth. The age of Sirius is estimated to be approximately 230 million years old, and it is expected to take about a billion years from its formation before using up all of the hydrogen at its core.

What's in the Name
- The name ̶0;Sirius̶1; comes from the Greek word ̶0;Seirios,̶1; meaning ̶0;searing̶1; or ̶0;scorching,̶1; which is a comment on its brilliance in comparison to other stars. Its nickname of the ̶0;Dog Star̶1; is based on its constellation, Canis Major, Latin for "the Greater Dog." This constellation represents the larger dog of Orion the Hunter from Greek mythology. Canis Minor is a separate constellation, which represents Orion̵7;s second dog.
Binary System
- What is seen from Earth as one star is actually a binary system, with two white stars orbiting each other so closely that they can̵7;t be distinguished from each other by the naked eye. The larger is known as Sirius A, or simply Sirius, while the smaller is designated as Sirius B. Although at one time it was the larger of the two, Sirius B is now a white dwarf and is sometimes referred to by the nickname ̶0;the Pup.̶1;
Visibility and Brightness
- Of all the stars in the night sky, Sirius is by far the brightest. The only objects that will appear brighter are planets in our own solar system: Venus, Jupiter, Mercury and Mars. The star's brightness is attributed to both its own luminosity -- 26 times more than the sun, according to astronomy professor Jim Kaler -- and the fact of its relatively close distance to Earth of 8.6 light years. Sirius can even be seen during the daytime under the right conditions.
Historical References
- Sirius has been observed, worshiped and used for navigation by cultures since ancient times. The Egyptians, for instance, noticed that the appearance of Sirius in the eastern sky coincided with the approach of the Nile's flooding season. This same time of year has been called the ̶0;dog days̶1; of summer, a term which can be traced to the Ancient Greeks. There are historical references to Sirius in many cultures, and they often refer to dogs.
Cultural References.
- Sirius̵7; significance can be seen in the numerous times it has been referred to in culture throughout the centuries. The name is used many times in music and literature, and its use is especially common in science fiction. Sirius, the satellite radio company, upon changing its name proudly announced it was being named ̶0;after the brightest star in the night sky.̶1; From Homer̵7;s ̶0;The Iliad̶1; (which mentions it as an evil portent) in the eighth century B.C., to Sirius Black (who can transform into a dog) in the ̶0;Harry Potter̶1; series, the name Sirius can be found again and again.

Astronomy