Astronomy quiz question: Altair's absorption line blueshift

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

Altair is a star with an apparent magnitude of m = +0.8, and is located 5.1 parsecs from Earth. The absorption lines in Altair's spectrum are slightly blueshifted, indicating that Altair 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): (C)

Absorption lines that are "blueshifted" means that they have slightly shorter wavelength values than expected (shifting all of them slightly towards the blue end of the spectrum), such that Altair is moving towards Earth.

Section 70160
Exam code: quiz05n0Ko
(A) : 0 students
(B) : 1 student
(C) : 20 students
(D) : 4 students

Success level: 81% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.02

No comments: