Astronomy quiz question: novae and type Ia supernovae

Astronomy 10 Quiz 8, Spring Semester 2007
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal Q10.3

[Version 1]

[3.0 points.] Which one of the following choices best describes a close-pair (mass-exchanging) binary system that can have many cycles of nova explosions?
(A) A massive main sequence star and a red dwarf.
(B) A black hole and a white dwarf.
(C) A supergiant and a white dwarf.
(D) A supergiant and a black hole.
(E) Two red dwarfs.

Correct answer: (C)
The hydrogen shed from a supergiant will form a degenerate layer around a white dwarf companion, and this outer layer will undergo fusion, producing a nova explosion.

Student responses
Section 4136
(A) : 6 students
(B) : 0 students
(C) : 26 students
(D) : 1 student
(E) : 0 students

[Version 2]

[3.0 points.] Which one of the following choices best describes a close-pair (mass-exchanging) binary system that can have a type Ia supernova explosion?
(A) A massive main sequence star and a red dwarf.
(B) A black hole and a white dwarf.
(C) A supergiant and a white dwarf.
(D) A supergiant and a black hole.
(E) Two red dwarfs.

Correct answer: (C)

When the hydrogen shed from a supergiant quickly forms a thick degenerate layer around a white dwarf companion (or the alternate theory is that this transfer has been going on for prolonged time over many nova explosion cycles), then the entire white dwarf will undergo fusion, producing a type Ia supernova explosion.

Student responses
Section 5076
(A) : 0 students
(B) : 2 students
(C) : 15 students
(D) : 1 student
(E) : 0 students