a system of two stars that revolve about their common center of mass.
Astronomical Curiosities J. Ellard Gore
The Astronomy of Milton’s ‘Paradise Lost’ Thomas Orchard
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
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.
- Binary system
a system involving only two elements, as 0 and 1 or yes and no. Mathematics. a system of counting or measurement whose units are powers of two. Compare binary (def 2a). Astronomy, binary star. Historical Examples The Astronomy of Milton’s ‘Paradise Lost’ Thomas Orchard The Phase Rule and Its Applications Alexander Findlay The Phase Rule […]
celebration of Mass twice on the same day by the same priest.
of or relating to two nations. Contemporary Examples What to Make of Le Mood’s Decision to Disinvite Speakers Over Israel Politics? Mira Sucharov November 3, 2013 Mexico’s Drug Wars Get Bloodier Charles Bowden March 19, 2010 The Man Who Tamed the Cocaine Capital Constantino Diaz-Duran October 18, 2010 The Killing of Guerrilla Leader Boosts Violence-Weary […]
Alfred [al-frid;; French al-fred] /ˈæl frɪd;; French alˈfrɛd/ (Show IPA), 1857–1911, French psychologist: co-deviser of the Binet-Simon scale. Historical Examples Dear Enemy Jean Webster Scaramouche Rafael Sabatini Scaramouche Rafael Sabatini Scaramouche Rafael Sabatini The Measurement of Intelligence Lewis Madison Terman Scaramouche Rafael Sabatini The Measurement of Intelligence Lewis Madison Terman Scaramouche Rafael Sabatini The Mind […]