The proper motion of a star is:
A) generally measured in kilometers/second.
B) measured from the Doppler shift.
C) calculated from the radial velocity.
D) generally larger for closer stars.

Question

Quizplus · Accepted Answer

Proper motion is the apparent motion of a star across the sky due to its own motion in space. It is measured in units of arcseconds per year. The motion is generally larger for closer stars and decreases as the distance increases. Therefore, option D is the correct answer. Option A is incorrect because the proper motion is not measured in kilometers per second. Option B is incorrect because proper motion is not measured from the Doppler shift, which measures the radial velocity of the star. Option C is also incorrect, as proper motion is not calculated from the radial velocity.

The Proper Motion of a Star Is