What is the Sun's absolute magnitude?

4.83 in the V-band. It is a fairly ordinary star in terms of intrinsic brightness.

What star has the lowest (brightest) absolute magnitude?

Extremely luminous stars like R136a1 have M around -8 to -9, outshining the Sun by millions of times.

It was chosen as a convenient round number that puts most nearby stars at moderate magnitude values.

Find a star's absolute magnitude from its apparent magnitude and distance: M = m - 5 log10(d/10).

Apparent Magnitude (m)

Distance

Absolute Magnitude

1.43 mag

Absolute Magnitude vs Apparent Magnitude (m)

Absolute magnitude (M) is the apparent magnitude a star would have at a standard distance of 10 parsecs.

M = m - 5 log10(d / 10)

This removes the effect of distance, allowing direct comparison of intrinsic brightnesses.

Sirius: m = -1.46 at d = 2.64 pc.

Find apparent magnitude from absolute magnitude and distance.

Find distance from magnitude difference.

Compute luminosity from absolute magnitude.