How does a radial velocity measurement depend on inclination?

1 Answer
Sep 21, 2017

The relative rate changes due to the geometry of the measurement.


If the orbital plane of the orbiting object happens to lie along our line of sight then the measured speed is the true speed of the wobble. However, if the orbital plane is tilted with respect to the Sun then the true speed is higher and the companion is more massive by a factor of #1/sin(i)#, where i is the angle of inclination.
Good explanation and graphics here:

An example is here:
The Variable Radial Velocity Of Sirius, and the Inclination of its Orbit-Plane

A student exercise here: