Initial Stellar Model
The stars obey a polytropic equation of state: P=χρ_{0}^{1+1/n}, with χ=constant. We choose n=1 to mimick stiff nuclear matter. In addition, the rotation law is given by
(u^{t})(u_{φ}) = (R_{eq})^{2} A^{2} (Ω_{c} - Ω),
where Ω is the angular velocity of the fluid, Ω_{c} is Ω on the rotation axis, and R_{eq} is the equatorial coordinate radius. A is a dimensionless parameter that measures the degree of differential rotation, chosen to be unity in the simulations. This rotation law has been found to be a good approximation to the angular velocity profile of proto-neutron stars formed from core collapse. In the Newtonian limit, it reduces to
Ω = Ω_{c} / (1 + r^{2}/R_{eq}^{2})
(r is the cylindrical radius.)
last updated 22 july 05 by dvd
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