20141213

Astronomy quiz question: type Ia supernova in distant galaxy

Astronomy 210 Quiz 7, fall semester 2014
Cuesta College, San Luis Obispo, CA

An observer in San Luis Obispo, CA detects a type Ia supernova in a distant galaxy right now. An observer inside that distant galaxy, very close to that location would observe right now a:
(A) nova.
(B) supergiant.
(C) white dwarf.
(D) type Ia supernova.
(E) medium-mass main-sequence star.
(F) (None of the above choices, as there is nothing left at that location right now.)

Correct answer (highlight to unhide): (F)

A type Ia supernova occurs when a white dwarf star takes hydrogen from a close binary companion star such that its carbon-oxygen core will have sufficient pressure to undergo fusion, and explode and completely destroy itself.

The finite speed of light results in information of events that occurred in the past taking time to reach distant locations, such that when we observe this type Ia supernova, the white dwarf has already exploded and is no more. An observer much closer to that location would have already seen that type Ia supernova explosion before us, and will now observe nothing remaining at that location.

Section 70158
Exam code: quiz07su4R
(A) : 1 student
(B) : 2 students
(C) : 13 students
(D) : 8 students
(E) : 3 students
(F) : 12 students

Success level: 33% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.17

Section 70160
Exam code: quiz07n0Lb
(A) : 2 students
(B) : 1 student
(C) : 13 students
(D) : 1 student
(E) : 2 students
(F) : 13 students

Success level: 45% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.24

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