noun
proper motion
Astronomical term for the apparent angular motion of a star across the sky, relative to more distant background objects.
バーナード星は固有運動が非常に大きいことで知られている。
Barnard's Star is known for its very large proper motion.
Compound of 固有 (こゆう, 'inherent, proper') and 運動 (うんどう, 'motion'), calque of English 'proper motion'.