Astronomy quiz question: type II supernova energy source

Astronomy 210 Quiz 5, Fall Semester 2010
Cuesta College, San Luis Obispo, CA

What provides the energy for a type II supernova explosion?
(A) Shockwaves from either nearby supernova explosions or hot young stars.
(B) Hydrogen fusion.
(C) Gravitational contraction.
(D) Convection.

Correct answer: (C)

Response (A) is how star formation may be triggered in the interstellar medium; response (D) is a consequence of heat from from the core to the surface of a star. Response (D) can no longer provide energy for a star at the end of its supergiant phase, as it core is iron at this point, past which requires more energy to be put in than can be released by fusion. Thus with no energy source to balance gravity, the core undergoes runaway contraction, and the resulting energy from this gravitational collapse of the core is transferred to the outer layers of the supergiant in an "implosion-explosion" sequence--a type II supernova.

Section 70158
(A) : 6 students
(B) : 5 students
(C) : 33 students
(D) : 0 students

"Success level": 77% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83