Simulations of Nonaxisymmetric Instability in a Rotating Star: A Comparison Between Eulerian and Smooth Particle Hydrodynamics
| Autor: | Joan Centrella, Janet L. Houser, Scott C. Smith |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1995 |
| Předmět: |
Physics
Angular momentum 010308 nuclear & particles physics Gravitational wave Astrophysics (astro-ph) FOS: Physical sciences Astronomy and Astrophysics General Relativity and Quantum Cosmology (gr-qc) Mechanics Astrophysics 01 natural sciences Potential energy General Relativity and Quantum Cosmology Rotational energy Smoothed-particle hydrodynamics Polytrope Gravitational field Space and Planetary Science 0103 physical sciences Quadrupole 010303 astronomy & astrophysics |
| Popis: | We have carried out 3-D numerical simulations of the dynamical bar instability in a rotating star and the resulting gravitational radiation using both an Eulerian code written in cylindrical coordinates and a smooth particle hydrodynamics (SPH) code. The star is modeled initially as a polytrope with index $n = 3/2$ and $T_{\rm rot}/|W| \approx 0.30$, where $T_{\rm rot}$ is the rotational kinetic energy and $|W|$ is the gravitational potential energy. In both codes the gravitational field is purely Newtonian, and the gravitational radiation is calculated in the quadrupole approximation. We have run 3 simulations with the Eulerian code, varying the number of angular zones and the treatment of the boundary between the star and the vacuum. Using the SPH code we did 7 runs, varying the number of particles, the artificial viscosity, and the type of initial model. We compare the growth rate and rotation speed of the bar, the mass and angular momentum distributions, and the gravitational radiation quantities. We highlight the successes and difficulties of both methods, and make suggestions for future improvements. Accepted by ApJ; to be published in Feb 10th, 1996 issue; 38 pages, figures NOT included; uuencoded, Z-compressed postscript version available via anonymous ftp at ftp://zonker.drexel.edu/papers/comparison WARNING: this document approx 7 Megs encoded and compressed, and 20 Megs uncompressed |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|