function dzdt = kepler_ode2Z(t,Z)
% assume 'Y' is a vector of form y = [ x ;y; z]
global rho sigma beta
%beta = 8/3;

x= Z(1);
y = Z(2);
z = Z(3);


dzdt =  x.*y - beta.*z;
dzdt = [0;0;dzdt];

        
