Sirius
From Conservapedia
Sirius, also known as Alpha Canis Majoris or the Dog Star, is the fifth closest star to our Solar System at 8.6 light years, and the brightest star in the sky with an apparent magnitude of -1.46[1]. It is located in the Constellation Canis Major and is a binary star system.
Contents |
History
Sirius A was known throughout human history and was referred to Sopdet by the ancient Egyptians. The Middle Kingdom of Egypt even based their calendar on the first day Sirius would become visible right before sunrise, to indicate the coming annual flooding of the Nile[2]. The star was called Sothis by the ancient Greeks, who viewed it as a herald that forewarned of a hot and dry summer ahead. Ptolemy was the first to actually map the star in the sky, recorded in the Almagest, or Great Book. It wasn’t until 1862 that Sirius B was observed and not until 1915 it was classified as a white dwarf[3].
The stars
The two stars in the Sirius binary system orbit each other with an average distance of 19.8 AU (around the distance of Uranus from the Sun), which takes around 50 years to complete. Sirius A is a star of spectral type A1V. Sirius B is a white dwarf star, which were once a more massive main sequence star then its companion. Scientists estimate the age of the system is only some 230 million years old[4].
Sirius A
Sirius A is the star that is seen from Earth and known since ancient times, it is the brightest star in the night sky. As an A1V class star, it appears somewhat bluish in color. The star is estimated to be over 2 times Sol’s mass and 1.68 to 1.71 its diameter. Sirius is also much hotter with a surface temperature 9,940K, but the largest difference between the star and our sun is the luminosity, where Sirius is more than 21 times brighter. Because of extreme brightness and temperature, the star is expected only to last another billion years before leaving the main sequence and becoming a Red Giant[4].
Sirius B
Nicknamed “the Pup”, Sirius B is a white dwarf and is more than 8,200 times as faint as it’s larger companion. The star is estimated to have about the same mass as out sun, but it’s diameter of 9,200 km is smaller than that of the Earth’s. Scientists theorize the star was once one of a spectral class B stars much like Regulus before becoming a red giant and finally a white dwarf[4].
Disambiguation
Sirius. also known as Sirius XM Radio, Inc. is also a subscription radio service most famous for hiring Howard Stern, but also offers a wide variety of stations appealing to different tastes, including stations devoted to Christian singers and Christian themes. Sirius merged with XM Satellite Radio on February 18, 2008.
