Meaning of spectroscopic binary

spec'troscop'ic bi'nary

Pronunciation: [key]
— Astron. Astron.
  1. a binary star having components that are not sufficiently separated to be resolved by a telescope, known to be a binary only bythe variations in wavelength of emitted light that are detected by a spectroscope. Cf.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.