A star that has an apparent magnitude of 0 (see Figure 10-2,Comins,Discovering the Essential Universe,6th ed.)would:
A) be fainter than Spica (α Virginis), which has an apparent magnitude of +1.0.
B) be brighter than Deneb (α Cygni), which has an apparent magnitude of +1.2.
C) have infinite brightness since 1/0 = infinity.
D) not be emitting any light and therefore could not be seen from Earth.

Question

Quizplus · Accepted Answer

A star with an apparent magnitude of 0 is considered to be the brightest star visible from Earth. Deneb has an apparent magnitude of +1.2, which is less bright than a star with an apparent magnitude of 0. Therefore, choice B is the correct answer. Option A is incorrect as Spica has an apparent magnitude of +1.0, which is less bright than a star with an apparent magnitude of 0. Option C is incorrect as infinity cannot be applied when it comes to the brightness of an object in astronomy. Option D is also incorrect as a star with an apparent magnitude of 0 emits a significant amount of light and can be seen from Earth.

A Star That Has an Apparent Magnitude of 0 (See