Star A and star B both have an absolute magnitude of 2.0, but star A is at a distance of 50 pcand star B is at a distance of 20 pc. Which statement below is correct?
A)Star A appears brighter than star B, but actually star B and star A are the same brightness.
B)Star B appears brighter than star A, but actually star B and star A are the same brightness.
C)Star A and star B appear to have the same brightness, but actually star B is brighter than starA.
D)Star A and star B appear to have the same brightness, but actually star A is brighter than starB.
E)It is impossible to determine how bright these stars are or appear to be relative to one another,given the information above.

Question

Quizplus · Accepted Answer

Because star A and star B have the same absolute magnitude, the only difference in their apparent brightness is due to their distance. The closer a star is, the brighter it appears. Since star B is closer than star A, it will appear brighter. However, both stars have the same intrinsic brightness. Star A and star B have the same absolute magnitude, so they are the same brightness if they were at the same distance. However, star B is closer than star A, so it appears brighter than star A. This is because the apparent brightness of a star is inversely proportional to the square of its distance. Therefore, star B appears brighter than star A, but actually they are the same brightness.

Star a and Star B Both Have an Absolute Magnitude