Astronomy quiz question: red dwarf metallicity

Astronomy 210 Quiz 7, spring semester 2018
Cuesta College, San Luis Obispo, CA

The amount of metals in the outer layers of metal-poor red dwarf will __________ over time.
(A) increase.
(B) remain constant.
(C) decrease.
(D) (A red dwarf cannot be metal-poor.)

Correct answer (highlight to unhide): (B)

Medium-mass and massive stars produce metals (elements heavier than hydrogen and helium) in their cores during their giant/supergiant phases, up through type Ia/II supernovae explosions. Along with their unused hydrogen, these metals are then scattered into the interstellar medium, which are then incorporated into later generations of stars. However, a red dwarf (low-mass star) will only be able to fuse hydrogen to helium, and does not produce more metals.

Section 30674
Exam code: quiz07nen4
(A) : 8 students
(B) : 10 students
(C) : 3 students
(D) : 1 student

Success level: 49% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.38

Section 30676
Exam code: quiz07SumM
(A) : 14 students
(B) : 9 students
(C) : 12 students
(D) : 3 students

Success level: 27% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.33