Castor, in astronomy

Castor (kăs`tər), bright star in the constellation Gemini Gemini (jĕm`ənī, –nē) [Lat.
..... Click the link for more information. ; Bayer designation α Geminorum; 1992 position R.A. 7^h34.1^m, Dec. +31°54'. Slightly dimmer than Pollux Pollux, brightest star in the constellation Gemini ; Bayer designation Beta Geminorum; 1992 position R.A. 7^h44.8^m, Dec. +28°03'. An orange giant of spectral class K0 III, it is the nearest giant star, lying at a distance of 35 light-years.
..... Click the link for more information. , with which it forms the Twins, Castor has an apparent magnitude magnitude, in astronomy, measure of the brightness of a star or other celestial object. The stars cataloged by Ptolemy (2d cent. A.D.), all visible with the unaided eye, were ranked on a brightness scale such that the brightest stars were of 1st magnitude and the
..... Click the link for more information. of 1.58, which still makes it one of the 25 brightest stars in the sky. Castor is actually a six-star system, being a visual triple each component of which is a binary star binary star or binary system, pair of stars that are held together by their mutual gravitational attraction and revolve about their common center of mass.
..... Click the link for more information. ; the three components are an eclipsing binary and a pair of spectroscopic binaries. The two brightest components are white, main-sequence stars of spectral classes spectral class, in astronomy, a classification of the stars by their spectrum and luminosity . In 1885, E. C. Pickering began the first extensive attempt to classify the stars spectroscopically.
..... Click the link for more information. A1 and A5. The system is about 50 light-years distant.

castor, in zoology

castor: see beaver beaver, either of two large aquatic rodents , Castor fiber and Castor canadensis, known for their engineering feats. They were once widespread in N and central Eurasia except E Siberia, and in North America from the arctic tree line to the S United
..... Click the link for more information. .

castor

1. the brownish aromatic secretion of the anal glands of a beaver, used in perfumery and medicine

2. the fur of the beaver

3. a less common name for beaver

castor (redirected from castors)

Castor, in astronomy

castor, in zoology

castor
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