spectroscopic binaries

Spectroscopic binaries are star systems where two stars orbit each other but are too close together to be seen separately through a telescope. Instead, astronomers detect them by observing the light that the stars emit. As the stars move towards and away from us in their orbits, their light shifts in color due to the Doppler effect—this results in changes in the wavelengths of the spectral lines. By studying these shifts, scientists can determine the stars' velocities, masses, and orbits, helping to unveil the dynamics of these hidden stellar pairs.