Initial Stellar Model
In each of the three simulations, the initial stars are differentially rotating polytropes, with n = 1:
P = K ρ_{0}^{Γ}, Γ = 1 + 1/n
with K and Γ constant. They each have a rest mass M_{0} = 0.20 in units where the maximum nonrotating mass is 0.17. The rotation law is given relativistically 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 the value of Ω on the rotation axis, and R_{eq} is the equatorial coordinate radius. A is a parameter that measures the degree of differential rotation, chosen to be 1 in the simulations. In the Newtonian limit, the rotation law is given by
Ω ≈ Ω_{c}/(1 + ϖ^{2}/R_{eq}^{2})
where ϖ is the cylindrical radius. Collapse is induced by depleting the initial pressure by a factor of 0.01.
last updated 23 jan 05 by pid
Center for Theoretical Astrophysics---University of Illinois at Urbana-Champaign Home | Research | Activities | Faculty | Postdocs | Graduate | Undergraduate | Movies |