Astronomy quiz question: IAU classification of Caduceus

Astronomy 210 Quiz 7, spring semester 2012
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.
Caduceus[*] is purported to be an irregularly shaped body in orbit around Mercury. If Caduceus was relocated to inside of Mercury's orbit around the sun, it would be:
(A) a moon.
(B) solar system debris.
(C) a dwarf planet.
(D) a planet.
(E) (None of the above choices.)

[*] http://messenger.jhuapl.edu/gallery/sciencePhotos/image.php?gallery_id=2&image_id=811.

Correct answer: (B)

Since Caduceus would be now relocated to directly orbit the sun (qualification I), but is still not rounded in shape (qualification II), this categorizes it as solar system debris.

Section 30674
Exam code: quiz07n4rS
(A) : 3 students
(B) : 20 students
(C) : 5 students
(D) : 1 student
(E) : 1 student

"Success level": 69% (including partial credit for multiple-choice)
Discrimination index (Aubrecht & Aubrecht, 1983): 0.56

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