Sirius

(redirected from Alpha Canis Majoris)
Also found in: Dictionary, Thesaurus.

Sirius

Sirius (sĭrˈēəs), or Dog Star, brightest star in the sky. It is located in the constellation Canis Major (1992 position R.A. 6h44.8m, Dec. −16°42′); its Bayer designation is Alpha Canis Majoris. Sirius [Gr.,=scorching], having an apparent magnitude of −1.45, is exceeded in brightness only by the sun, the moon, and Venus and by Mars and Jupiter at their maximum brightness. A white, main-sequence star of spectral class A1 V, Sirius is about twice the size of the sun and about 20 times as luminous. It is also one of the nearest stars, lying at a distance of 8.7 light-years, so that it has been studied extensively. From an analysis of its motions, F. W. Bessel concluded (1844) that it had an unseen companion, which was later (1862) confirmed by observation. The companion, Sirius B, is a white-dwarf star and has also been the object of considerable study because it is the first white dwarf whose spectrum was found to exhibit a gravitational red shift as predicted by the general theory of relativity.
The Columbia Electronic Encyclopedia™ Copyright © 2022, Columbia University Press. Licensed from Columbia University Press. All rights reserved.

Sirius

(seer -ee-ŭs, si -ree-) (Dog Star; α CMa) A white main-sequence star that is the brightest one in the constellation Canis Major and the brightest (after the Sun) and one of the nearest stars in the sky. It lies in a descending (southeasterly) line from Orion's Belt. Sirius is about 1.5 times as hot as the Sun, with a surface temperature of more than 9000 K, and is about 23 times as luminous. It is a visual binary (separation 4″.6, period 50 years), the companion, Sirius B, being the first white dwarf to be discovered. Bessel suggested (1844) that Sirius had a dark companion to account for the star's wobbling movement. With improved telescope lenses Alvan G. Clark detected (1862) a tiny companion whose spectrum, first taken (1915) by W.S. Adams Jr., identified Sirius B as a white dwarf. The spectrum demonstrated the gravitational redshift predicted by the general theory of relativity. mv : –1.46 (A), 8.3 (B); Mv : 1.4 (A), 11.2 (B); spectral type: A1 Vm (A), DA (B); mass: 2.31 (A), 0.98 (B) times solar mass; radius: 1.7 (A), 0.022 (B) times solar radius; distance: 2.65 pc.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Sirius

 

(α Canis Majoris), the brightest star in the heavens, with a visual stellar magnitude of — 1.46. Sirius has a luminosity 22 times greater than that of the sun; its distance from the sun is 2.7 parsecs. Sirius is a system of two stars: the satellite of Sirius, a star 10,000 times fainter than Sirius itself, was the first white dwarf to be discovered.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

Sirius

[′sir·ē·əs]
(astronomy)
The brightest-appearing star in the sky; 8.7 light-years from the sun, spectral class A1V; it has a white dwarf companion. Also known as Dog Star.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

Sirius

dog star; brightest star in the heavens. [Astronomy: EB, IX: 238]
Allusions—Cultural, Literary, Biblical, and Historical: A Thematic Dictionary. Copyright 2008 The Gale Group, Inc. All rights reserved.