Astronomy quiz question: coolest star?

Astronomy 210 Quiz 5, spring semester 2017
Cuesta College, San Luis Obispo, CA

Which star is the coolest?
(A) A0 supergiant.
(B) M5 giant.
(C) F5 main-sequence star.
(D) B5 white dwarf.
(E) (There is a tie.)

Correct answer (highlight to unhide): (D)

An H-R diagram is provided with this quiz.

These stars are plotted on an H-R diagram below. The M5 giant is the coolest, followed by the F5 main-sequence star, the A0 supergiant, and the B5 white dwarf is the hottest. Instead of using the H-R diagram, the OBAFGKM mnemonic can be used to determine the temperatures of these stars from their spectral type.

Section 30676
Exam code: quiz05s4Ha
(A) : 3 students
(B) : 29 students
(C) : 0 students
(D) : 7 students
(E) : 2 students

Success level: 72% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.74

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