The star Alderamin has an apparent magnitude of 2.4 and an absolute magnitude of 1.4.The star Merak has an apparent magnitude of 2.4 and absolute magnitude of 0.5.Assuming that neither star has been dimmed by interstellar clouds,we can say for sure that Merek is:
A) the same distance as Alderamin from Earth.
B) farther away from Earth than Alderamin.
C) an intrinsically fainter star than Alderamin.
D) closer to Earth than Alderamin.

Question

Quizplus · Accepted Answer

Both stars have the same apparent magnitude of 2.4, but Merak has a brighter absolute magnitude of 0.5 compared to Alderamin's absolute magnitude of 1.4. This means that Merak is intrinsically brighter than Alderamin. However, both stars have the same apparent magnitude, which is simply a measure of how bright they appear from Earth. Therefore, the only possible explanation for this is that Merak is farther away from Earth than Alderamin, which would cause it to appear equally as bright despite being intrinsically brighter.

The Star Alderamin Has an Apparent Magnitude of 2