Astronomy current events question: Elias 2-27's protoplanetary disk spiral arms

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

Students are assigned to read online articles on current astronomy events, and take a short current events quiz during the first 10 minutes of lab. (This motivates students to show up promptly to lab, as the time cut-off for the quiz is strictly enforced!)

Valeria Foncea, Charles E. Blue, Richard Hook, and Masaaki Hiramatsu
, "ALMA Discovers Hidden Spiral Arms Embracing a Young Star" (September 29, 2016)
almaobservatory.org/en/press-room/press-releases/1043-alma-discovers-hidden-spiral-arms-embracing-a-young-star

Spiral dust patterns surrounding star Elias 2-27 observed by the Atacama Large Millimeter/submillimeter Array (ALMA) may be caused by:
(A) nucleosynthesis.
(B) radioactive decays.
(C) a black hole companion.
(D) planet formation.
(E) fusion instabilities.

Correct answer: (D)

Student responses
Sections 70178, 70186
(A) : 4 students
(B) : 4 students
(C) : 2 students
(D) : 15 students
(E) : 3 students