Radial velocity curves are plotted for a binary star system. The two curves cross when one star begins approaching and the other star begins receding, then cross again when they reverse, and then cross a third time when the first star again begins approaching. Which statement is TRUE about this set of curves?

Question

Quizplus · Accepted Answer

At the crossing points, the radial velocity is not necessarily zero because it depends on the orientation of the orbit and the angle of inclination with respect to Earth. The other statements are not necessarily true, as the times between the crossings can vary depending on the period of the orbit and the magnitudes of the maximum radial velocities can differ depending on the masses of the stars. Additionally, the radial velocities of the two stars do not have to be equal and opposite at any given point.

Radial Velocity Curves Are Plotted for a Binary Star System