Question

CHECK MY ANSWER:

Which of the following is used to determine if a star is moving closer to Earth?

Absolute magnitude
Brightness
Doppler shift
Parallax

I was debating between C and D but think it is D.

Answer 1

This is Doppler Shift (C).  As the emitting object moves closer to an observer, the waves shift to a higher frequency called a blue shift.  Moves away called a red shift (lowering of the frequency)

Answer 2

Answer:

Doppler shift

Explanation: