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

Spiral-Mode Instability
24-bit Quicktime format

Fragmentation of Protostellar Disks

"Massless" Torus
Self-Gravitating Torus

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

Merger of Close, Equal-Mass Binary Stars

Stable Binary
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

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.