Absolute Magnitude

13.2 - Understand the term absolute magnitude

Absolute magnitude is a useful way of finding out how bright a star would appear from a certain point in space. By doing this we understand each star's true magnitude.

The true absolute magnitude for the Sun is 4.2 whereas to us on Earth it is -27.

It is the brightness of a star at a distance of 10 parsecs which is 32.6 light years.

In calculations apparent magnitude is represented by M.

 

Summary

M = m + 5 - 5 log D

M = Absolute Magnitude
m= apparent magnitude

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Curious about Astronomy? How do astronomers measure the brightness of stars?