Astronomy current events question: TW Hydrae dusty disk water vapor

Astronomy 210L, fall semester 2011
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!)

Astronomy.com editors, "Herschel Finds Oceans of Water in Disk of Nearby Star," October 21, 2011
http://astronomy.com/en/News-Observing/News/2011/10/Herschel%20finds%20oceans%20of%20water%20in%20disk%20of%20nearby%20star.aspx

The Herschel Space Observatory detected _________, which may be evidence of cold water vapor in a dusty disk around the star TW Hydrae.
(A) radioactive comets.
(B) lightning flashes.
(C) cooler than expected temperatures.
(D) infrared light from molecules.
(E) ice crystal reflections.

Correct answer: (D)

Student responses
Sections 70178, 70186, 70200
(A) : 1 student
(B) : 0 students
(C) : 10 students
(D) : 21 students
(E) : 17 students