Radial velocity
GLOSSARY
RADIAL VELOCITY
The speed at which an object is moving away or toward an observer.
Due to the Doppler-Fizeau effect, this motion results in shifting of the
spectral lines from their standard positions (redshift if the object
moves away, blueshift if the object moves toward the observer).
By observing the position of the spectral lines, astronomers can determine how fast objects are moving away from or toward us; however, these spectral lines cannot be used to measure how fast the objects are moving across the sky.
In the case of a binary system of stars, measuring the radial velocities of the two components makes possible to determine the characteristics of the orbit of the system.
By observing the position of the spectral lines, astronomers can determine how fast objects are moving away from or toward us; however, these spectral lines cannot be used to measure how fast the objects are moving across the sky.
In the case of a binary system of stars, measuring the radial velocities of the two components makes possible to determine the characteristics of the orbit of the system.