Core Collapse Supernovae An Emerging Picture Stephen W. Bruenn 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Collaborators Anthony Mezzacappa John M. Blondin John C. Hayes Oak Ridge National Lab North Carolina State UC at San Diego W. Raph Hix Oak Ridge National Lab O. E. Bronson Messer Oak Ridge National Lab 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Core Collapse Supernova Energetics Photons ~ 10 49 ergs Ejecta Kinetic energy ~ 10 51 ergs Neutrinos ~ 3x10 53 ergs 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Core Collapse Supernova Polarization Asymmetries Core collapse SN are polarized at ~1% level Degree of polarization increases with decreasing envelope mass Degree of polarization generally increases after optical maximum Outward mixing of Ni in SN1987 A & Cas A Axisymmetric ejecta of SN1987A Early Emission of x-rays and γ-rays from SN1987A Pulsar kicks 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Direct Imaging SN 1987A Suggests a Bipolar Structure SN 1987A November 28, 2003
Supernova Connections Neutron Stars Nucleosynthesis Supernovae Neutrino Signatures Black Holes Gravitational Waves
Core Collapse Supernova Scenario neutrinos shock
Aftermath neutrinos photons matter neutron star or black hole
The Supernova Problem Matter Flow Neutrino flow Shock _ ν e + n p + e - ν e + p n + e + _ ν e + n p + e - ν e + p n + e + Protoneutron Star Gain Radius ν-spheres Cooling Heating
The Core Collapse Supernova Mechanism: A Computational Challenge Inherently multi-dimensional Variety of complex physical processes that need to be accurately modeled Explosions are marginal 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Supernova Code Hydrodynamics Nuclear Reactions Neutrino Transport
Hydrodynamics Lagrangian PPM with Remap implementation of a Godunov scheme Newtonian spectral Poisson solver with effective GR radial potential Spherical polar grid Moving radial grid option during infall, adaptive below shock after shock generation 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Hydrodynamics Implementation 2500 2000 1500 e i + e k + e g in shock if! < 10 13 g cm -3, e i + e k in shock if! > 10 13 g cm -3, e i elsewere evolve e i + e k + e g, remap e i + e k e i + e k in shock, e i elsewere e i + e k + e g everywhere e i + e k everywhere 11.2 M O 1D. Improved Opacities evolve e i + e k, remap e i + e k + e g 1000 500 e i + e k + e g if! < 10 13 g cm -3, e i + e k if! > 10 13 in shock, e i outside of shock if! > 10 13 0 0 0.1 0.2 0.3 0.4 0.5 t post bounce (s)
Nuclear Network 4 He, 12 C, 16 O, 20 Ne, 24 Mg, 28 Si, 32 S, 36 Ar, 40 Ca, 44 Ti, 48 Cr, 52 Fe, 56 Ni, 60 Zn n, p, Fe-like tracers Advection of material into and out of NSE Flashing and freeze-out of zones 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Neutrino Transport Multigroup, flux-limited diffusion tuned to Boltzmann transport Ray-by-ray plus approximation Full flavor implicit solve All O(v/c) velocity corrections, red shift and time dilation effects included 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
Neutrino Interactions Emission and Absorption of ν e s e + p, A(Z, N) ν e + p, A(Z 1, N + 1) Emission and Absorption of ν e s e + + n, A(Z, N) ν e + p, A(Z + 1, N 1) Neutrino-Electron, Neutrino-Positron Scattering ν e,µ,τ, ν e,µ,τ + e, e + ν e,µ,τ, ν e,µ,τ + e, e + Neutrino Scattering on Nucleons and Nuclei ν e,µ,τ, ν e,µ,τ + n, p, A ν e,µ,τ, ν e,µ,τ + n, p, A Electron-Positron Pair Annihilation e + e + ν e,µ,τ + ν e,µ,τ Nucleon-Nucleon Bremsstrahlung N + N N + N + ν e,µ,τ + ν e,µ,τ Neutrino-Neutrino Scattering ν e,µ,τ + ν e,µ,τ ν e,µ,τ + ν e,µ,τ
Progenitor Structure 12 10 11.2 M Ȯ 15.0 M Ȯ 8 20.0 M Ȯ 6 4 2 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Mass Enclosed (M O ).
S15s7b 15 ms post bounce
S15s7b 100 ms post bounce
S15s7b 200 ms post bounce
S15s7b 621 ms post bounce
20M 256x256 O.
2D Supernova Simulations Stellar Mass Gravity Opacities Resolution 20 Groups t (ms pb) Explosion Energy (B) Remnant (M O ). 11 (S11s7b) N Standard 192 X 32 610 Y 0.18 1.43 11 (S11s7b) N Standard 192 X 96 646 Y 0.23 1.43 11.2 (S11.2) N Improved 256 X 128 262 Y 0.1 1.30 11.2 (S11.2) GR Improved 256 X 128 319 Y 0.27 1.31 11.2 (S11.2) N Improved 256 X 256 429 Y 0.36 1.30 11.2 (S11.2) GR Standard 256 X 256 589 Y 0.19 1.34 11.2 (S11.2) GR Improved 256 X 256 372 Y 0.30 1.31 15 (S15s7b) N Standard 192 X 32 680 Y 0.14 1.54 15 (S15) N Improved 256 X 256 269 15 (S15) GR Improved 256 X 256 180 20 (S20) N Improved 256 X 256 379 Possibly 20 (S20) GR Improved 256 X 256 307 Possibly
Why Are We Getting Explosion? Convection driven by neutrino heating Improved neutrino rates Energy deposition by nuclear reactions SASI (Standing Accretion Shock Instability) 19th Rencontres de Blois Matter and Energy in the Universe: from nucleosynthesis to cosmology
SASI
Neutrinospheres Neutrinospheres Heating Cooling Protoneutron Star! e s _! e s _! µ s,_! µ s,! " s,! " s,! e -sphere _! e -sphere! µ & " -sphere
1D Supernova Simulations 150 S11.2, 63 ms post bounce 100 50 0-50 -100-150 shock em - ab! - e -,e + scat! +! - e - + e +! + N scat N + N brem Net 1x10 7 1x10 8 1x10 9 1x10 10 1x10 11 1x10 12 " (g cm -3 )
1D Supernova Simulations Neutrino Luminosities 45 40 35 30 25 11.2 M O GR 1D. Stand opacities Stand + Brem opacities Stand + (! + N) opacities Stand + Brem + (! + N) opacities 20 15 10 5 0 0 0.5 1 1.5 2 2.5 t post bounce (s)
Conclusions 2D simulations with spectral neutrino transport exhibit explosions for the 11.2 and 20M models, and probably for the 15M model as well. The simulations must be continued for longer times to ascertain the explosion energies of the models.
Future Work Investigate the observables of the exploding models---nucleosynthesis, neutrino and gravitational wave signatures, neutron star masses and kick velocities. Move to 3-D Use a singularity-free grid Incorporate magnetic fields