peculiar velocity
Quick Summary
Peculiar velocity, also known as peculiar motion, refers to the actual movement of a star after accounting for the Sun's motion. This is determined by correcting the observed proper motion and radial velocity of a star.1
Proper motion measures a star's movement across the line of sight, perpendicular to the observer. Radial velocity measures its motion toward or away from the observer, detected through shifts in spectral lines (redshift for recession, blueshift for approach).2
By combining these measurements with a star's parallax, astronomers can calculate its total space motion.2
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