Astronomy & Space Science · AST-597
Astrometry & Transit Timing Variations: Structures & Vocabulary
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Structure
Structure of Astrometry & Transit Timing Variations
Astrometric detection measures tiny periodic shifts of a star's sky position around the barycenter. Transit timing variations compare observed transit times with a perfectly periodic ephemeris; deviations arise when planets gravitationally perturb one another.
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- 01How We Find and Characterize ExoplanetsOpen source ↗
NASA Science
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Astrometry and transit timing variations detect planets through changes in stellar position or in the timing of other planets rather than through brightness depth or Doppler speed alone.
supported · checked Sep 22, 2026Precision astrometry measures stellar reflex motion, while Kepler systems exhibit repeatable timing patterns that require interacting planets.
supported · checked Sep 22, 2026A companion displaces the host star around the center of mass, producing an angular wobble whose size increases for massive planets on wider orbits and nearby stars.
supported · checked Sep 22, 2026