The Formation of Binary Star Systems

Joel E. Tohline
John E. Cazes
Howard S. Cohl

Department of Physics & Astronomy
Louisiana State University

1. Astronomy Background

Hubble Deep Field
Galaxy M100
Orion Nebula
Orion Animation

2. Summary of Research

Basic Physics
Ellipsoidal Figures of Equilibrium

Figure 1

3. Computational Tools

CFD Algorithm
Visualization Tools (Alias/Wavefront on the SGI Onyx)
Heterogeneous Computing Environment

4. Example Simulations

Fission of Rapidly Rotating Protostars

MOVIE
Spiral-Mode Instability
24-bit Quicktime format
(2,554K)

MOVIE
Velocity flow-Field
in the Bar
mpeg
(2,421K)

Fragmentation of Protostellar Disks

MOVIE
"Massless" Torus
 MOVIE
Self-Gravitating Torus

Quicktime format (834K)
24-bit mpeg format (515K)
mpeg format (190K)

Merger of Close, Equal-Mass Binary Stars

MOVIE
Stable Binary
 MOVIE
Binary Merger

Quicktime format (834K)
 mpeg format (701K)

5. High Peformance Fortran (HPF) and High-Performance-Computing

Early Experiences on the Cray T3E
Single-Processor Performance on the T3E

NAVOCEANO MSRC: T3E_900
Test Compiler Streams Execution Speed (MFlops)
Grid size
64 × 32 × 32 		Grid size
67 × 34 × 32
E1 F90 OFF 7.74 24.88
E2 ON 8.85 38.19
F1 PGHPF OFF 15.07 15.41
F2 ON 23.08 23.31

6. What Next?

Visualization: Include tracer particles with volume-rendered images.
"Cool" ellipsoidal structure to see if Binary Fission occurs.
Study the stability of unequal-mass binary systems (Patrick Motl).
Improvements in gravitational CFD algorithms.

7. Acknowledgments

This research has been supported, in part, by the following grants, programs, and institutions:

The U.S. National Science Foundation through grant AST-9528424.
A grant of high-performance computing time at the San Diego Supercomputer Center.
A grant of high-performance computing time through the PET program at the U.S. Naval Oceanographic Office's Major Shared Resource Center in Stennis, Mississippi, U.S.A.
A LaSPACE Fellowship awarded to J.E.Cazes.