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, one can say for sure that Merak 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

The absolute magnitude of a star indicates its intrinsic brightness. Since Merak has a higher absolute magnitude (0.5) compared to Alderamin (1.4), but both have the same apparent magnitude (2.4), it means Merak is intrinsically brighter but appears as bright as Alderamin from Earth because it is farther away.

The Star Alderamin Has an Apparent Magnitude of 2