A star with planets orbiting in a plane that is not face- on to our line- of- sight exhibit a Doppler effect due to .
A)the planet's mass shifting the path of light from the star
B)the light reflecting from the moving planets
C)the light emitted by the moving planets
D)the planet gravitationally tugging the star

Question

Quizplus · Accepted Answer

The Doppler effect is caused by the gravitational tug of the planet on the star, which causes the star to move slightly towards and away from us. This motion causes the observed wavelength of the light emitted by the star to be shifted slightly towards the blue end of the spectrum (when moving towards us) or towards the red end of the spectrum (when moving away from us). This shift in wavelength is what allows astronomers to detect the presence of planets around other stars. The other answer choices do not accurately describe the cause of the Doppler effect in this context.

A Star with Planets Orbiting in a Plane That Is