If we restrict our measurements to a specific band of color or wavelength using an optical filter,what observations of a star are necessary to determine the absolute magnitude of the star at this color?
A) distance and temperature
B) apparent magnitude and temperature
C) just apparent magnitude since absolute magnitude is simply apparent magnitude +5
D) apparent magnitude and distance

Question

Quizplus · Accepted Answer

In order to determine the absolute magnitude of a star at a specific color using an optical filter, we need to know the distance to the star (to account for its brightness at that distance) and the apparent magnitude (to differentiate its brightness at that specific color from other colors). Temperature is not necessary for determining absolute magnitude at a specific color. Absolute magnitude is not simply apparent magnitude +5, as that is only true for stars with a specific distance of 10 parsecs.

If We Restrict Our Measurements to a Specific Band of Color