The star alpha Proxima Centauri, the nearest star beyond the Sun, is 22 km closer to the Sun every second. This motion of alpha Proxima Centauri toward the Sun is an example of
A) radial velocity.
B) precession.
C) elongation.
D) proper motion.

Question

Quizplus · Accepted Answer

Radial velocity refers to the motion of an object either towards or away from the observer, in this case, the Sun. Since alpha Proxima Centauri is moving closer to the Sun, this motion is described as radial velocity.

The Star Alpha Proxima Centauri, the Nearest Star Beyond the Sun