You observe the same spectral line in two stars that are identical in every way except that one rotates faster than the other. How does the spectral line differ between the two?
A) There is no difference.
B) The line in the faster rotating star is blueshifted.
C) The line in the faster rotating star is redshifted.
D) The line in the faster rotating star is broader.
E) The line in the faster rotating star is narrower.
Answer: D