L = (4πR^{2}) σT^{4}

L = f 4πd^{2}

R = [\frac{fd^{2}}{σT^{4}} ]^{1/2}

R = \sqrt{\frac{fd^{2}}{σT^{4}}}

P^{2} = \frac{4π^{2}}{GM} a^{3}

M = \frac{4π^{2}}{GP^{2}} a^{3}

\frac{ΔM}{M} = (\frac{Δa}{a})^{3} = (\frac{Δdist}{dist})^{3}