Absolute Magnitude of a Star - with parallax

Description

Absolute magnitude is the measure of a celestial object’s intrinsic brightness. It is the hypothetical apparent magnitude of an object at a standard luminosity distance of exactly 10.0 parsecs or about 32.6 light years from the observer, assuming no astronomical extinction of starlight. This allows the true energy output of astronomical objects to be compared without regard to their variable distances. As with all astronomical magnitudes, the absolute magnitude can be specified for different wavelength intervals; for stars the most commonly quoted absolute magnitude is the absolute visual magnitude, which is the absolute magnitude in the visual (V) band of the UBV system.

In the Euclidean approximation for nearby objects, the absolute magnitude of a star can be calculated from its apparent magnitude and parallax, as shown.