BRAINCAKEAbsolute Magnitude
Apparent magnitude depends on distance, so it cannot be used to compare how powerful stars really are. The absolute magnitude, M, of a star is defined as the apparent magnitude it would have if it were at a distance of 10 parsecs from Earth. Comparing absolute magnitudes compares the stars' actual power outputs (luminosities).
Apparent magnitude m, absolute magnitude M and distance d are linked by:
m − M = 5 log (d / 10)
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More in Astrophysics
- Radio Telescopes
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- Apparent Magnitude
- Parsecs and Light Years
- Black-Body Radiation
- Wien's Displacement Law
- Stefan's Law
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All 24 lessons in Astrophysics · All AQA A-level Physics topics