The Doppler technique can be used to estimate the semimajor axis of a planet's orbit by
A)measuring the speed at which the star orbits the mutual center- of- mass of the star and planet, and using Newton's theory of gravity.
B)measuring the amount by which the starlight is reduced when the planet transits.
C)measuring the time it takes for the star's line- of- sight velocity to cycle from peak to peak, and using Newton's version of Kepler's Third law.
D)measuring the asymmetries in the velocity curve.

Question

Quizplus · Accepted Answer

The Doppler technique measures the slight variations in a star's radial velocity caused by the gravitational pull of an orbiting planet. By measuring the periodicity of these velocity variations, the orbital period of the planet can be determined. Newton's version of Kepler's Third law can then be used to relate the orbital period to the semimajor axis of the planet's orbit.

The Doppler Technique Can Be Used to Estimate the Semimajor