Current Work

Core-Collapse Explosion Mechanism

• 2D Simulations using Smooth Particle Hydrodynamics (SPH)

For code description and modifications, see: Herant et al. 1994; Fryer et al. 1999; Fryer & Heger 2000.

Because 3D simulations are so computationally intensive, we must use 2D simulations to direct our 3D simulations. Recent studies of rotating progenitors indicate that rotation can produce large asymmetries in supernova explosions (Fryer & Heger 2000).


• Symmetric SN Explosion (11.9MB)

from a non-rotating 15 Solar Mass progenitor (Fryer & Heger 2000). Colors denote radial velocity (red is falling inward, blue outward).
• Asymmetric SN Explosion (14.5MB)

from a rotating 15 Solar Mass progenitor. Rotation limits convection along the angular momentum axis, leading to stronger explosions in these polar regions.


• 3D SPH Simulations
The main effort at LANL is to produce 3-dimensional core-collapse simulations to study asymmetries in core-collapse. These asymmetries may explain a host of observations from mixing and polarization to neutron star space velocities and spin rates.
• Dec. 20: Slice of 3D Collapse Model

for a non-rotating 15 Solar Mass progenitor. This plot is of a low resolution (300,000 particle) test simulation 0.3s after collapse. The shock has now moved to 500km and the star is exploding (Warren & Fryer).
• Dec. 29: Rendering of 3D collapse model(171MB) - Single Snapshot(52kB)

showing the convective upwells in the 15 Solar Mass model 40 ms after bounce. The surface in this plot is an isosurface of the material moving outward at 1000 km/s. The shading is denotes the temperature.
• Jan. 8: Time Evolution (38MB)

of the 15 Solar Mass star. The surface in this plot is an isosurface of the material moving outward at 1000 km/s and the simulation runs from 35ms after bounce to nearly 100ms after bounce. We have run this model for another 150ms at which time the explosion energy is 2.9 times ten to the Fifty-One Ergs (foe) and the remnant mass is 1.15 solar masses (compare to 3 foe and 1.1 solar masses for a comparable 2D run).
• June 2: Paper I

from 3D SPH simulations, accepted by ApJ (LAUR-02-2610).
• June 3: latest movie (16.3 Mbytes)

from 3D SPH simulations. The surface denotes an isosurface of material moving with radial velocities at 1000km/s.
• June 3: 2-d slice through the center (3.5 Mbytes)

of a 3D SPH simulation. The vectors are colored by entropy, and their length is proportional to the particle velocity.

Explosion Simulations

• 3D SPH simulations of the explosion out to late times (1 yr)

Core-collapse simulations indicate that supernova explosions are asymmetric. But can these asymmetries explain the supernova observations (X-ray and Gamma-ray lines, polarization, light curves, nucleosynthetic yields)? To compare the asymmetries seen in core-collapse simulations with supernova observations, we must follow the explosion out to late times. Here we show the first simulations of these explosions.

• Movie of a polar explosion (1.9MB)

from a 15 Solar Mass progenitor (Hungerford, Fryer,& Warren - in preparation). Colors denote mean atomic weight.
• Equatorial explosion at 1 yr (0.2MB: LAUR-02-2217)

from a 15 Solar Mass progenitor. The solid data shows the Cobalt distribution. The decay of the radioactive Cobalt produces the gamma-rays detected in the observations.
• Dec. 21: Jet explosion at 1 yr (171MB) - Single Snapshot (0.17MB: LAUR-02-2217)

from a 15 Solar Mass progenitor. The solid data shows the Cobalt distribution. The decay of the radioactive Cobalt produces the gamma-rays detected in the observations.

Computing Resources

• Space Simulator

Our new 665 Gflop Beowulf Cluster for our supernova calculations.

Papers

Sponsored by:
LANL
Los Alamos National Labs

Beomax Sales and Services


SciDAC
The Department of Energy
Scientific Discovery Through Advanced Computing
and

ASCI
Accelerated Strategic Computing Initiative

Created by Chris Fryer