Assessing the Effects of New Reaction Rates and Convection Theory on Studies of Supernova Progenitors

Project: Research project

Project Details


We request funding to carry out a systematic evaluation of nuclear reaction rates and convection on the pre-explosion evolution of core-collapse (SN II) and thermonuclear (SN Ia) supernovae. We will use MESA (Modules for Experiments in Stellar Astrophysics) a new stellar evolution computer code that is co-authored by Co-PI Timmes. One goal of this proposal is to determine the effects of new thermonuclear reaction rates, taken from the next-generation library STARLIB developed by Co-PI Iliadis, on the resulting evolution. Another goal is to test the effects of the latest convection theory, microphysics <br/>changes, and numerical techniques on the results. STARLIB is a first-of-its-kind nuclear reaction rate library and, unlike all other libraries, it contains the full reaction rate probability densities at all stellar temperatures. It is publicly available as of June 2013. Consequently, we are now in a unique position to model stellar evolution and nucleosynthesis in a quantitative manner that makes predictions for key observations by NASA ground-based and satellite observatories. We will use two complementary strategies. First, we will take the modern and multiple prescriptions of convection that are implemented <br/>in MESA, together with the recommended thermonuclear reaction rates provided by STARLIB, to generate new hydrodynamic simulations of SN Ia and SN II progenitor evolution. Second, we will take the temperature-density-time trajectories from the evolutionary results and do Monte Carlo post-processing nucleosynthesis calculations by sampling over the reaction rate probability densities. This procedure could not be applied previously and has only become feasible with the availability of STARLIB. Calculations of pre-supernova evolution with the STARLIB reaction rates and new convection prescriptions will provide, for the first time, statistically rigorous estimates for both their evolutionary structures and resulting nucleosynthesis. Significant insight into pre-supernova evolution will be obtained from the comparison of our simulations to the large amount of spectroscopic and photometric data available to us from both NASA satellites and ground based observatories. We will use these data, combined with our simulations, to make predictions that can be tested against both archival and new observations from NASA ground-based and satellite observatories and thereby advance our understanding of supernovae. This proposal is directly relevant to two of the top three recommendations (Cosmic Dawn and Physics of the Universe) in the 2010 Decadel Survey of Astronomy and Astrophysics New Worlds, New Horizons. It is also directly relevant to part of the Science Goals in the 2013 ROSES Call for Proposals (page 39): ``Astrophysics: Discover how the universe works and explore how the universe began and evolve''. We also cover the following Topic Categories (listed on page D.4-2): 2) Stellar Astrophysics and Exoplanets, 3) Collapsed Objects and X-ray Astrophysics, and 4) Supernovae and Gamma Ray Bursts.
Effective start/end date8/10/158/9/20


  • NASA: Goddard Space Flight Center: $676,687.00


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