Advancements in Modeling Self-Consistent Core-Collapse Supernovae with CHIMERA

University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 8-2012 Advancements in Modeling Self-Consistent Core-Collapse Supernovae with CHIMERA Merek Austin Chertkow University of Tennessee, Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Other Astrophysics and Astronomy Commons Recommended Citation Chertkow, Merek Austin, "Advancements in Modeling Self-Consistent Core-Collapse Supernovae with CHIMERA. " PhD diss., University of Tennessee, 2012. https://trace.tennessee.edu/utk_graddiss/1463 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Merek Austin Chertkow entitled "Advancements in Modeling Self-Consistent Core-Collapse Supernovae with CHIMERA." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Physics. William Hix, Major Professor We have read this dissertation and recommend its acceptance: Kate Jones, Mike Guidry, Robert, Hinde Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Advancements in Modeling Self-Consistent Core-Collapse Supernovae with CHIMERA A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Merek Austin Chertkow August 2012 c by Merek Austin Chertkow, 2012 All Rights Reserved. ii Dedication I lovingly dedicated this dissertation to my sister Blair, who has always been my counselor on the ways and truths of life; to my brother Adam, who will always be the builder to my architect; my mother Rhonda, who has taught me the truest meaning of love; and to my father Merek, thank you for your name, I hope I've made you proud. iii Acknowledgments The work composing my thesis and dissertation is certainly not a product of my efforts alone, but rather, of a closely knit group of highly skilled people, all pushing towards an understanding of supernovae at, what we lovingly refer to as, the bleeding edge of computational astrophysics. When I began working on my Ph.D., I knew very little about working with supercomputers and numerical programs with architectures as large as CHIMERA's. Therefore, for for their guidance and extreme patience in helping mentor me throughout the years, I want to give special thanks to Dr. Bronson Messer and Dr. Reuben Budiardja. In addition, were it not for the comradeship and debates on the principles of physics with Dr. Suzanne Parete-Koon, I would have had a serious lack of people to complain to and bounce silly ideas off of. I want to acknowledge the years of guidance and help from Dr. Eric Lentz and Dr. Steve Bruenn, without whom my thesis simply could not have existed. A great thanks to Dr. Bruenn for all of his insightful answers to my sometimes seemingly strange questions and inquiries about the physics and applications of our code. Thanks to Dr. Lentz for his mini-physics lessons that became one-man seminar lectures { I've learned so very much. And finally, I want to express the depth of my gratitude towards Dr. William Raph Hix for being the kind of mentor and advisor every graduate student should be fortunate enough to have. His methods of stewardship with my research project has iv helped me become a resolved and independent researcher. His guidance has meant the world to me on both a professional and friendship level. Finally, the simulations described herein were conducted at the Oak Ridge Lead- ership Computing Facility at ORNL and at the National Institute for Computational Sciences. This work was supported in part by NSF grants NSF-AST-0653376, NSF- PHY-0855315, NSF-OCI-0749242, NSF-OCI-0749204 & NASA grant 07-ATFP07- 0011. MAC and WRH acknowledge support from the Office of Nuclear Physics, US Department of Energy, and from the Office of Advanced Scientific Computing Research, US Department of Energy. v Abstract Using a sophisticated program named CHIMERA, we perform numerical simulations of the end of a massive star's life when its core can no longer support itself through electron degeneracy pressure. After a violent collapse to super-nuclear densities, the core releases its binding energy (1053 ergs) in the form of neutrinos. Simulations have shown that a small fraction of these neutrinos' energy is deposited into the matter above the forming neutron star, which drives a delayed explosion. Throughout this process, the oxygen and lighter elements that had composed the star's outer- core and envelope experience shock-driven explosive nucleosynthesis, forming newly synthesized heavy elements up to the iron and nickel At later times in the ejecta, other processes, such as the νp-process and possibly the r-process, create elements heavier than iron, which are required to match galactic and solar abundance studies. To follow these nuclear kinetics accurately and to more judiciously model reality, CHIMERA requires an efficient nuclear reaction network of approximately 150 to 300 species. I will discuss my efforts in generalizing CHIMERA's 14-species nuclear reaction network to enable us to more accurately follow the proton-to-nucleon fraction within a complex hydrodynamic flow and the nuclear production and nuclear energy generation rates that results. I will discuss how these improvements have enabled the study of the lower mass limit of core-collapse supernovae. I will discuss the development of our post-processing scheme to extract detailed nucleosynthesis from our state-of-the-art multi-dimensional CHIMERA runs. vi Contents 1 Introduction1 1.1 Our CCSNe Simulation Code, CHIMERA...............3 1.2 Nucleosynthesis with CHIMERA....................4 1.3 Nuclear Networks.............................6 1.4 Thesis Workflow..............................7 2 The Death of Massive Stars 10 2.1 Non-Explosive Stellar Thermonuclear Burning............. 12 2.2 The Core-Collapse Phase......................... 14 2.3 The Bounce and Stalled Shock Accretion Phase............ 14 2.4 The Neutrino-Heating Explosion Mechanism.............. 15 2.5 Explosive Burning and the Ejecta.................... 17 3 Modeling Core Collapse Supernovae 21 3.1 Modeling with CHIMERA........................ 24 3.2 Building a CHIMERA Progenitor.................... 26 4 Calculating Detailed Nucleosynthesis 28 4.1 Extending Thermonuclear Reaction Networks Towards Realism... 32 4.2 Results and Challenges of a Large Network............... 35 5 The Passive Tracer Particle Method 43 5.1 Tracer Particle Analysis......................... 45 vii 5.2 The Tracer Particle Reader....................... 46 5.3 A Lagrangian Perspective........................ 48 5.4 CHIMERA's 2009 Simulations...................... 51 5.5 CHIMERA's 2012 Simulations...................... 60 5.6 Gravitational Waves From Tracer Data................. 64 5.7 Conclusion on Tracer Particles...................... 68 6 Electron Capture Supernovae from ONeMg-Core Progenitors 72 6.1 Nomoto's 1987 8.8 M Progenitor.................... 76 6.2 Evolving ECSNe with CHIMERA.................... 80 6.3 ECSN Conclusions............................ 88 7 Conclusion 93 Appendix 103 Vita 106 viii List of Tables 5.1 Boundedness criterion for tracer particles................ 55 5.2 Current status of the 2012 CHIMERA 2D Runs............ 62 ix List of Figures 1.1 Workflow on nucleosynthesis results and contributions of this thesis to the CHIMERA project..........................9 3.1 CHIMERA's 3D pilot run in preparation for full production models.. 25 4.1 Mass Fractions during a post-processing nucleosynthesis calculation.. 34 4.2 1D testing of a 15 M model using a large and small network.... 36 4.3 Significant nuclear abundances of 150 and 14 species networks.... 38 4.4 Significant nuclear abundances of the 150-species network....... 39 4.5 The timing difference between a small and large nuclear network... 40 4.6 Cost of a large network with OpenMP................. 41 5.1 2009-25M - Tracer particle trajectory examples............ 49 5.2 25 M - Tracer Particles atop hydrodynamic flow of entropy greyscale map.................................... 50 5.3 25M - Tracer Particles breaking spherical symmetry......... 51 5.4 Explosion energies of 2009 simulations................. 53 5.5 Mass of boundedness criteria with binned tracers for 2009-S25M... 55 5.6 Final distribution of tracer particles from 2009-25M binned by their boundedness criteria........................... 56 5.7 Extrapolated tracer particle data to determine freezeout....... 57 5.8 Detailed nucleosynthesis for 2009-25p1010............... 58 5.9 νp-process nucleosynthesis for 2009-25p759............... 59 x 5.10 Density profile of the iron-core models................. 61 5.11 Shock radius vs post-bounce time of 2012 CHIMERA run....... 63 5.12 Snapshot of the entropy distribution for 2012-12M........... 64 5.13 Snapshot of the entropy distribution for the 2012-15M......... 65 5.14 Snapshot of the entropy distribution for 2012-20M........... 65 5.15 Snapshot of the entropy distribution for 2012-25M........... 66 5.16 Explosion energies

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