optical double star

double star

noun Astronomy.
  1. two stars that appear as one if not viewed through a telescope with adequate magnification, such as two stars that are separated by a great distance but are nearly in line with each other and an observer (optical double star), or those that are relatively close together and comprise a single physical system (physical double star).
Compare binary star.

Origin of double star

First recorded in 1775–85
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for optical double star

double star

noun
  1. two stars, appearing close together when viewed through a telescope; either physically associated (binary star) or not associated (optical double star)See also binary star, optical double star

optical double star

noun
  1. two stars that appear close together when viewed through a telescope but are not physically associated and are often separated by a great distanceCompare binary star
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

optical double star in Science

double star

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