The Experts below are selected from a list of 44505 Experts worldwide ranked by ideXlab platform
Paul Tupper - One of the best experts on this subject based on the ideXlab platform.
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the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
Astrophysical Journal Supplement Series, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction-rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from seven different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak = 0.145 to 0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A = 40. In total, we performed ≈7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction-rate evaluations for the mass ranges A = 1-20 and 20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on currently uncertain nuclear physics input, while for the experimental nuclear physicist, our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction-rate estimates are reliable for predictions of Li, Be, C, and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl, and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
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the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
arXiv: Astrophysics, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
Thomas Rauscher - One of the best experts on this subject based on the ideXlab platform.
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Essentials of Nucleosynthesis and Theoretical Nuclear Astrophysics
2020Co-Authors: Thomas RauscherAbstract:Essentials of Nucleosynthesis and Theoretical Nuclear Astrophysics provides a concise summary of the most important concepts and equations related to Nucleosynthesis and theoretical nuclear astrophysics and is a suitable basis for a graduate course on these topics.
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Nuclear Reactions For Nucleosynthesis Beyond Fe
2015Co-Authors: Thomas RauscherAbstract:Many more nuclear transitions have to be known in the determination of stellar reactivities for trans-iron Nucleosynthesis than for reactions of light nuclei. This requires different theoretical and experimental approaches. Some of the issues specific for trans-iron Nucleosynthesis are discussed.
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Proton-rich Nucleosynthesis and nuclear physics
2012Co-Authors: Thomas Rauscher, Carla FröhlichAbstract:Although the detailed conditions for explosive Nucleosynthesis are derived from astrophysical modeling, nuclear physics determines fundamental patterns in abundance yields, not only for equilibrium processes. Focussing on the νp- and the γ-process, general Nucleosynthesis features within the range of astrophysical models, but (mostly) independent of details in the modelling, are presented. Remaining uncertainties due to uncertain Q-values and reaction rates are discussed.
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New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis
Journal of Nuclear Science and Technology, 2002Co-Authors: Robert D. Hoffman, Thomas Rauscher, Alexander Heger, S. E. WoosleyAbstract:We review the current status of the nuclear reaction rates needed to study Nucleosynthesis in massive stars. Results for the calculated Nucleosynthesis of all stable species from Hydrogen to Bismuth in a completely evolved 25 M⊙ star of initial solar metallicity will be presented. Special emphasis will be paid to two particular reactions, 12C(α, γ)16O and 22Ne(α, n)25Mg, and their effect on the structure of the star and resultant Nucleosynthesis. Both have been measured many times, but the present range of experimental uncertainty translates into remarkable sensitivity of the calculated Nucleosynthesis.
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NUCLEAR ASPECTS OF Nucleosynthesis IN MASSIVE STARS
Hadrons Nuclei and Applications, 2001Co-Authors: Thomas Rauscher, Alexander Heger, R. D. Hoffman, S. E. WoosleyAbstract:Preliminary results of a new set of stellar evolution and Nucleosynthesis calculations for massive stars are presented. These results were obtained with an extended reaction network up to Bi. The discussion focuses on the importance of nuclear rates in pre- and post-explosive Nucleosynthesis. The need for further experiments to study specific reactions and nuclear properties (optical alpha+nucleus potentials) is emphasized.
Christian G Iliadis - One of the best experts on this subject based on the ideXlab platform.
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Statistical methods for thermonuclear reaction rates and Nucleosynthesis simulations
Journal of Physics G, 2015Co-Authors: Christian G Iliadis, Francis Timmes, Richard Longland, Arthur E ChampagneAbstract:Rigorous statistical methods for estimating thermonuclear reaction rates and Nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and γ-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from Nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and Big Bang Nucleosynthesis.
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the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
Astrophysical Journal Supplement Series, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction-rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from seven different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak = 0.145 to 0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A = 40. In total, we performed ≈7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction-rate evaluations for the mass ranges A = 1-20 and 20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on currently uncertain nuclear physics input, while for the experimental nuclear physicist, our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction-rate estimates are reliable for predictions of Li, Be, C, and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl, and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
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the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
arXiv: Astrophysics, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
S. E. Woosley - One of the best experts on this subject based on the ideXlab platform.
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Nucleosynthesis in Early Neutrino Driven Winds
AIP Conference Proceedings, 2008Co-Authors: R. D. Hoffman, S. E. Woosley, J. L. Fisker, Jason Pruet, Hans-thomas Janka, R. BurasAbstract:Two recent issues realted to Nucleosynthesis in early proton‐rich neutrino winds are investigated. In the first part we investigate the effect of nuclear physics uncertainties on the synthesis of 92Mo and 94Mo. Based on recent experimental results, we find that the proton rich winds of the model investigated here can not be the only source of the solar abundance of 92Mo and 94Mo. In the second part we investigate the Nucleosynthesis from neutron rich bubbles and show that they do not contribute to the Nucleosynthesis integrated over both neutron and proton‐rich bubbles and proton‐rich winds.
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New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis
Journal of Nuclear Science and Technology, 2002Co-Authors: Robert D. Hoffman, Thomas Rauscher, Alexander Heger, S. E. WoosleyAbstract:We review the current status of the nuclear reaction rates needed to study Nucleosynthesis in massive stars. Results for the calculated Nucleosynthesis of all stable species from Hydrogen to Bismuth in a completely evolved 25 M⊙ star of initial solar metallicity will be presented. Special emphasis will be paid to two particular reactions, 12C(α, γ)16O and 22Ne(α, n)25Mg, and their effect on the structure of the star and resultant Nucleosynthesis. Both have been measured many times, but the present range of experimental uncertainty translates into remarkable sensitivity of the calculated Nucleosynthesis.
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NUCLEAR ASPECTS OF Nucleosynthesis IN MASSIVE STARS
Hadrons Nuclei and Applications, 2001Co-Authors: Thomas Rauscher, Alexander Heger, R. D. Hoffman, S. E. WoosleyAbstract:Preliminary results of a new set of stellar evolution and Nucleosynthesis calculations for massive stars are presented. These results were obtained with an extended reaction network up to Bi. The discussion focuses on the importance of nuclear rates in pre- and post-explosive Nucleosynthesis. The need for further experiments to study specific reactions and nuclear properties (optical alpha+nucleus potentials) is emphasized.
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Nucleosynthesis in massive stars and supernovae
Nuclear Physics A, 1997Co-Authors: S. E. Woosley, R. D. Hoffman, Francis Timmes, Thomas A. Weaver, F. K. ThielemannAbstract:Abstract We briefly summarize some recent work on Nucleosynthesis in massive stars and supernovae. Here we explore: 1) the effect of including additional sources of Nucleosynthesis besides massive stars into the mixture - especially classical novae and several varieties of Type Ia supernovae; 2) the sensitivity of the results to choices of theoretical nuclear reaction rates in the mass range 28 ≤ A ≤ 70; 3) Nucleosynthesis above the iron group using a much larger reaction network; and 4) the sensitivity of these results to recent revisions in experimental reaction rates for isotopes A ≤ 28. For the recently revised rates, 17 O is no longer a massive star product.
Arthur E Champagne - One of the best experts on this subject based on the ideXlab platform.
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Statistical methods for thermonuclear reaction rates and Nucleosynthesis simulations
Journal of Physics G, 2015Co-Authors: Christian G Iliadis, Francis Timmes, Richard Longland, Arthur E ChampagneAbstract:Rigorous statistical methods for estimating thermonuclear reaction rates and Nucleosynthesis are becoming increasingly established in nuclear astrophysics. The main challenge being faced is that experimental reaction rates are highly complex quantities derived from a multitude of different measured nuclear parameters (e.g., astrophysical S-factors, resonance energies and strengths, particle and γ-ray partial widths). We discuss the application of the Monte Carlo method to two distinct, but related, questions. First, given a set of measured nuclear parameters, how can one best estimate the resulting thermonuclear reaction rates and associated uncertainties? Second, given a set of appropriate reaction rates, how can one best estimate the abundances from Nucleosynthesis (i.e., reaction network) calculations? The techniques described here provide probability density functions that can be used to derive statistically meaningful reaction rates and final abundances for any desired coverage probability. Examples are given for applications to s-process neutron sources, core-collapse supernovae, classical novae, and Big Bang Nucleosynthesis.
-
the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
Astrophysical Journal Supplement Series, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction-rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from seven different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak = 0.145 to 0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A = 40. In total, we performed ≈7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction-rate evaluations for the mass ranges A = 1-20 and 20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on currently uncertain nuclear physics input, while for the experimental nuclear physicist, our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction-rate estimates are reliable for predictions of Li, Be, C, and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl, and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
-
the effects of thermonuclear reaction rate variations on nova Nucleosynthesis a sensitivity study
arXiv: Astrophysics, 2002Co-Authors: Christian G Iliadis, Arthur E Champagne, Sumner Starrfield, J Jose, Paul TupperAbstract:We investigate the effects of thermonuclear reaction rate uncertainties on nova Nucleosynthesis. One-zone Nucleosynthesis calculations have been performed by adopting temperature-density-time profiles of the hottest hydrogen-burning zone (i.e., the region in which most of the Nucleosynthesis takes place). We obtain our profiles from 7 different, recently published, hydrodynamic nova simulations covering peak temperatures in the range from Tpeak=0.145-0.418 GK. For each of these profiles, we individually varied the rates of 175 reactions within their associated errors and analyzed the resulting abundance changes of 142 isotopes in the mass range below A=40. In total, we performed 7350 nuclear reaction network calculations. We use the most recent thermonuclear reaction rate evaluations for the mass ranges A=1-20 and A=20-40. For the theoretical astrophysicist, our results indicate the extent to which nova Nucleosynthesis calculations depend on presently uncertain nuclear physics input, while for the experimental nuclear physicist our results represent at least a qualitative guide for future measurements at stable and radioactive ion beam facilities. We find that present reaction rate estimates are reliable for predictions of Li, Be, C and N abundances in nova Nucleosynthesis. However, rate uncertainties of several reactions have to be reduced significantly in order to predict more reliable O, F, Ne, Na, Mg, Al, Si, S, Cl and Ar abundances. Results are presented in tabular form for each adopted nova simulation.
