How does the radial velocity method reveal the star's movement along our line of sight?

Answer

Through measurable shifts (blueshift/redshift) in the star’s spectral lines.

As the star moves toward Earth, its light spectrum is compressed (blueshift), and as it moves away, it is stretched (redshift). This shift in spectral lines allows measurement of the velocity toward or away from us.

How does the radial velocity method reveal the star's movement along our line of sight?
measurementastronomyexoplanetsdetection