binary star

See synonyms for binary star on
  1. a system of two stars that revolve about their common center of mass.

Origin of binary star

First recorded in 1875–80

Words Nearby binary star Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use binary star in a sentence

  • With reference to this well-known binary star, Burnham says, “the elements of the orbit are very accurately known.”

    Astronomical Curiosities | J. Ellard Gore
  • A star shown to be double by the spectroscope, but not by the telescope, is called a spectroscopic binary star.

    Astronomy for Young Folks | Isabel Martin Lewis

British Dictionary definitions for binary star

binary star

  1. a double star system comprising two stars orbiting around their common centre of mass. A visual binary can be seen through a telescope. A spectroscopic binary can only be observed by the spectroscopic Doppler shift as each star moves towards or away from the earth: Sometimes shortened to: binary See also optical double star, eclipsing binary

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for binary star

binary star

  1. A system of two stars that orbit a common center of mass, appearing as a single star when visible to the unaided eye. The orbital periods of binary stars range from several hours to several centuries. By some estimates, at least half of the stars in the Milky Way galaxy are members of binary star systems. Also called double star♦ Binary stars are divided into four main classes based on how their dual nature is detected. A visual binary can be resolved telescopically into its two components. Only one star of an astrometric binary is visible, but the unseen component can be identified from its gravitational effect on the visible star, causing it to oscillate slightly, or wobble, against the background of more distant stars. The two components of a spectroscopic binary are identified based on their varying orbital velocities toward or away from Earth as revealed by periodic Doppler shifts in their spectral lines. In an eclipsing binary, the two components orbit each other in such a way that they periodically obscure or eclipse each other as viewed from Earth, causing changes in their observed brightness. Eclipsing binaries are also considered a kind of variable star.♦ Two stars that lie very close to each other along an observer's line of sight but that are not associated with each other in a gravitational system are known as optical binaries. Although they appear close to each other in the sky, such stars are actually very distant from each other in space. See also multiple star variable star.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.