Initial Stellar Model

In each of the three simulations, the initial stars are differentially rotating polytropes, with n = 1:

P = K ρ₀^Γ,    Γ = 1 + 1/n

with K and Γ constant. They each have a rest mass M₀ = 0.20 in units where the maximum nonrotating mass is 0.17. The rotation law is given relativistically by:

u^tu_φ = R_eq² A² (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 + ϖ²/R_eq²)

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