function g = grot(w,x,theta);
% function to compute local surface gravity for a
% rotating star.
%
% D. Holmgren holmgren@phobos.astro.uwo.ca

% put in stellar parameters here...
G = 6.67e-11; M = 1.5913e31; Rp = 2.7851e9;
gpole = G*M/Rp^2;
A = 27/(8*x^2) - w^2*x*sin(theta)^2;
B = w^4*x^2*sin(theta)^2*cos(theta)^2;
gn = (8/27)*sqrt(A*A - B);
g = gn*gpole*100;