An astronomer whose secret hobby is riding merry-go-rounds has dedicated his career to finding the stars that rotate the most rapidly. But the stars are all very far away, so none of them can be seen to spin even when he looks through the largest telescopes. How then can he identify the stars that rotate rapidly?
A) all stars that rotate show a huge Doppler shift toward the blue end of the spectrum
B) stars that rotate have a significantly lower luminosity than stars that do not rotate
C) stars that rotate have much wider lines in their spectra than stars that do not
D) stars that rotate bring the light atoms (like hydrogen) spinning up to their surfaces; so they can be identified by the elements they contain
E) this astronomer better spend some more time enjoying his hobby, because he is not doing well at his job; there is no way we know about today to identify stars that rotate

Question

Quizplus · Accepted Answer

Stars that rotate rapidly have wider lines in their spectra than stars that do not. This is known as the rotational broadening effect, where the rotation of the star causes its spectral lines to broaden due to the Doppler effect. Therefore, the astronomer can identify stars that rotate rapidly by looking for stars with wider lines in their spectra.

An Astronomer Whose Secret Hobby Is Riding Merry-Go-Rounds Has Dedicated