The Universe

Watching Supernova Shock Breakouts in 3D

Image showing 4 views from a supernova shock breakout simulation
Volume renderings of a supernova shock breakout showing radiation energy density (top left); gas density (top right); gas pressure (bottom left); and magnitude of the velocity field (bottom right). At time 0, the shock is injected from the inner boundary of the simulation domain. Before this, the movies show the turbulent structures near the surface, which evolve slowly. After the shock passes through the envelope for 20 hours, the star is rotated to demonstrate very anisotropic shock breakout emission. Yan-Fei Jiang, Flatiron Institute; Nina McCurdy, NASA/Ames

When a massive red supergiant star dies, its core collapses first, generating strong shocks that propagate outwards through the stellar envelope while still maintaining the properties—such as radius and surface structures—of the original star. By observing the “shock breakout”—a bright flash that occurs when the supernova’s shock reaches the surface of the star—astrophysicists can discover a lot of information about the star’s properties and about the collapse of its core. To help improve our understanding of these observations, researchers from the Flatiron Institute’s Center for Computational Astrophysics ran 3D radiation hydrodynamic simulations of red supergiant stars’ convective envelope, then simulated the propagation of a strong shock from the collapse of the star through the convective envelope. Their results show that convection in red supergiant stars can cause large-scale fluctuations of the stellar photosphere, which can significantly broaden the shock breakout signatures when compared with predictions based on 1D stellar evolution models. These simulation results have important implications for future observations of shock breakouts.

Quick Facts

Our 3D radiation hydrodynamic simulations of massive stars require hundreds of processor cores to run and a large amount of run time to get meaningful results. This work would be impossible without the supercomputing resources provided by NASA.

Yan-Fei Jiang,
Flatiron Institute
  • Each 3D simulation ran across 150 Skylake nodes of NASA’s Electra supercomputer for a month to obtain the 3D structures of the stellar envelopes. Then the simulations were run again with supernova shocks incorporated to obtain the shock breakout signatures.
  • Results showed that convection in the envelope of red supergiant stars can cause significant fluctuations of the stellar photosphere, significantly broadening the number of shock breakout signatures available to help astrophysicists interpret future observations.
  • The light curves generated from the simulations can be directly compared with shock breakout observations and constrain the properties of the original star.
  • Next steps include determining the spectrum evolution of the light curves and exploring shock breakout signatures from different types of progenitor stars, such as red supergiants with varying masses, and yellow supergiants.

Researcher

  • Yan-Fei Jiang, Flatiron Institute

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