Astronomy midterm question: Sun as a pulsar?

Astronomy 10 Midterm 3, Spring Semester 2008
Cuesta College, San Luis Obispo, CA

Astronomy 10 learning goal M3.5
[15 points.] Decide whether our Sun will ever become a pulsar. If so, then discuss how this process will occur. If not, then discuss why this process cannot occur. Explain using the properties and evolution of stars.

Solution and grading rubric:

• p = 15/15:
  Correct. Adequately describes either what the Sun would eventually become (white dwarf), or why the Sun cannot become a neutron star (pulsar).
  
• 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 demonstrates understanding that the Sun is not massive enough to become a supergiant -> type II supernova -> neutron star, and/or understands the properties of a pulsar that presumably cannot be attained by the medium-mass Sun.
  
• v = 6/15:
  Limited relevant discussion of supporting evidence of at least some merit, but in an inconsistent or unclear manner. Explains that the Sun will become a pulsar, or explains that the Sun cannot become a pulsar because it is too massive.
  
• 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.
  

Grading distributions:
Section 4160
p: 9 students
r: 3 students
t: 10 students
v: 9 students
x: 7 students
y: 1 student
z: 1 student

Section 5166
p: 11 students
r: 5 students
t: 14 students
v: 22 students
x: 3 students
y: 0 students
z: 0 students

A sample "p" response (from student 0223):
Another "p" response (from student 4607), perhaps looking to be disappointed when the Sun does not go out with a bang: