Astronomy quiz question: start of a type II supernova

Astronomy 210 Quiz 5, spring semester 2013
Cuesta College, San Luis Obispo, CA

A type II supernova begins when a supergiant:
(A) accumulates enough hydrogen from a companion star.
(B) removes energy from its core using fusion.
(C) has too much radioactivity.
(D) generates strong stellar winds.

Correct answer (highlight to unhide): (B)

A massive star will fuse elements heavier than hydrogen to produce energy during its supergiant phase. However, once the core has been fused into iron, fusion of iron into heavier elements takes in energy instead of releasing energy, and the supergiant no longer has a source of energy to support itself against gravity. The interior of the supergiant will then collapse in on itself, triggering the "implosion-explosion" of a type II supernova.

Response (A) is what would trigger either a nova or a type Ia supernova of a white dwarf with a close binary companion star; response (D) is when a medium-mass star goes through its planetary nebula phase.

Section 30674
Exam code: quiz05n3wT
(A) : 14 students
(B) : 11 students
(C) : 0 students
(D) : 0 students

Success level: 49% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.75