astrophysics - Relationship between absolute magnitude of a star and its luminosity?

• Why does this relationship involves the absolute magnitude of the sun and its luminosity?


• How to derive an expression relating the absolute magnitude of a star to its luminosity?

So according to the magnitude equation, $$m - M = 2.5logleft(frac{d^2}{d_0^2}right)$$
$$Rightarrow M = m - 2.5logleft(frac{d^2}{d_0^2}right) (eq1)$$

and Luminosity is $$L = 4pi(d^2) times f$$
$$Rightarrow d^2 = frac{L}{4pi times f} (eq2)$$

Plugging eq2 to eq1 would have seem reasonable, but how is absolute magnitude of the sun and its luminosity used?