Three stars have the following absolute (M) and apparent (m) magnitudes. Star A: M = 1.8 m = 3.8
Star B: M = 2.5 m = 9.5
Star C: M = 7.6 m = 15.1
Which star is closest to Earth?
A) Star A
B) Star B
C) Star C
D) cannot be determined from these data

Question

Quizplus · Accepted Answer

The distance to a star can be determined using the distance modulus formula, which relates a star's absolute magnitude (M), apparent magnitude (m), and distance (d) in parsecs: m - M = 5 log(d) - 5. The smaller the difference between m and M, the closer the star is to Earth. Star A has the smallest difference (3.8 - 1.8 = 2), indicating it is the closest.

Three Stars Have the Following Absolute (M) and Apparent (M)