20161014

Astronomy quiz question: meeting only first IAU planetary qualification

Astronomy 210 Quiz 4, fall semester 2016
Cuesta College, San Luis Obispo, CA

Refer below to the minimal qualifications established by the International Astronomical Union for a planet:
I. Orbits the sun.
II. Shape "rounded-out" by gravity.
III. Cleared/dominates orbit around sun.
Which solar system object(s) only meets qualification I, but does not meet qualifications II and III?
(A) Mars.
(B) The moon.
(C) Haumea, a dwarf planet.
(D) Virginia, a small asteroid.
(E) (More than one of the above choices.)
(F) (All of the above choices.)
(G) (None of the above choices.)

Correct answer (highlight to unhide): (D)

Mars orbits the sun (meets I); is "rounded out" in shape (meets II); and does not share its orbit around the sun (meets III).

The moon orbits Earth (and does not directly orbit the sun, failing qualification I); is "rounded out" in shape (meeting qualification II); and does not dominate its orbit around the sun (failing qualification III), as it is gravitationally bound to orbiting Earth as Earth orbits the sun.

Haumea orbits the sun (meets I); is "rounded out" in shape (meets II); but does not dominate its orbit around the sun, sharing it with other Kuiper Belt objects (fails III).

Virginia orbits the sun (meets I); its shape is not "rounded out" (fails II); and does not dominate its orbit around the sun, sharing it with other asteroids (fails III).

Thus Virginia is the only object listed here that only meets qualification I, but does not meet qualifications II and III.

Section 70158
Exam code: quiz04s5ie
(A) : 0 students
(B) : 2 students
(C) : 3 students
(D) : 22 students
(E) : 6 student
(F) : 0 students
(G) : 1 student

Success level: 68% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.70

Section 70160
Exam code: quiz04n4uG
(A) : 3 students
(B) : 2 students
(C) : 1 student
(D) : 15 students
(E) : 4 student
(F) : 0 students
(G) : 1 student
(No responses: 1 student)

Success level: 60% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.83

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