Cuesta College, San Luis Obispo, CA
Astronomy 10 learning goal Q10.3
[15 points.] Describe and explain what causes repeated nova explosions.
Solution and grading rubric:
- p = 15/15: Correct.
A giant or supergiant overflows its Roche lobe, depositing hydrogen onto a white dwarf companion, which by itself cannot have fusion. When enough hydrogen gathers onto the surface of the white dwarf, then it will become dense enough and hot enough to undergo fusion. The process then repeats itself, as long as there is hydrogen still being taken from the giant/supergiant. - r = 12/15:
Nearly correct (explanation weak, unclear or only nearly complete); includes extraneous/tangential information; or has minor errors. - t = 9/15:
Contains right ideas, but discussion is unclear/incomplete or contains major errors. At least recognizes that hydrogen is transferred between two stars in a close-pair ("mass-exchanging") system. - v = 6/15:
Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. - x = 3/15:
Implementation/application of ideas, but credit given for effort rather than merit. - y = 1.5/15:
Irrelevant discussion/effectively blank. - z = 0/15:
Blank.
Section 4136
p: 18 students
r: 0 students
t: 3 students
v: 3 students
x: 9 students
y: 0 students
z: 1 student
A portion of a "p" response (from T. B.):
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