Cuesta College, San Luis Obispo, CA
At right is shown an H-R diagram of a(n) __________ star cluster. (A) extremely young.
(B) middle-age.
(C) extremely old.
(D) (This H-R diagram is not possible for a star cluster.)
Correct answer: (D)
This star cluster is not possible. While the massive stars have come and gone, and the medium-mass stars are now in the middle of their main-sequence lifetimes, there are notably no low-mass stars anywhere in this diagram (whether in the protostar or main-sequence stage, unless they have inexplicably gone left "past" the main-sequence line), and there are also some medium-mass stars that have already gone through their giant stages, strangely enough having already become white dwarfs.
Section 30674
Exam code: quiz05n4rA
(A) : 1 student
(B) : 4 students
(C) : 2 students
(D) : 31 students
"Success level": 83% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.30
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