If a Seyfert galaxy's nucleus varies in brightness on the timescale of 10 hours,then approximately what is the size of the emitting region?
A) 20 AU
B) 70 AU
C) 90 AU
D) 140 AU

Question

Quizplus · Accepted Answer

The timescale of 10 hours for brightness variation suggests that the emitting region is around the size of our solar system, which is approximately 70 AU. Choice A (20 AU) is too small, choice C (90 AU) is slightly larger, and choice D (140 AU) is too large.

If a Seyfert Galaxy's Nucleus Varies in Brightness on the Timescale