Astronomy quiz question: Eta Aurigae's absorption line redshift

Astronomy 210 Quiz 5, fall semester 2016
Cuesta College, San Luis Obispo, CA

Eta Aurigae is a star with an apparent magnitude of m = +3.2, and is located 75 parsecs from Earth. The absorption lines in Eta Aurigae's spectrum are slightly redshifted, indicating that Eta Aurigae is:
(A) slightly cooler than expected.
(B) slightly warmer than expected.
(C) moving towards Earth.
(D) moving away from Earth.

Correct answer (highlight to unhide): (D)

Absorption lines that are "redshifted" means that they have slightly longer wavelength values than expected (shifting all of them slightly towards the red end of the spectrum), such that Eta Aurigae is moving away from Earth.

Section 70158
Exam code: quiz05s4nD
(A) : 9 students
(B) : 2 students
(C) : 5 students
(D) : 21 students

Success level: 58% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.80

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