L = \frac{1}{nπd^{2}}

Luminosity = 4πR^{2} σ T_{eff}^{4}

f(v, v + Δv) = (\frac{m}{2πkT} ) e^{(−mv^{2}/2kT)} 4πv^{2}Δv

v_{rms} = \sqrt{\frac{3kT}{m}}

dI = −I ρκds

\frac{dI}{I} = −ρκds

\frac{I}{I_{0}} = e^{−ρκs}

ρκs = 1  ⇒  s = \frac{1}{ρκ}

I = I_{0} e^{−ρκs}  becomes  I = I_{0} e^{−τ}

σ_{bf} = 1.31 × 10^{−19} \frac{1}{n^{5}} (\frac{λ}{5000 Å})^{3} m^{2}