Equation 1 and 2 can now be combined by setting T = T eff and P = P 0 in Equation 1, then eliminating P 0 . R can be eliminated using Equation 3. After some algebra, and after setting γ γ = 5 / 3 , we get: ln ⁡ ⁡ T eff = A ln ⁡ ⁡ L + B ln ⁡ ⁡ M + c o n s t where A = 0.75 a − − 0.25 5.5 a + b + 1.5 B = 0.5 a + 1.5 5.5 a + b + 1.5