Deciphering Fingerprints of Stellar Nucleosynthesis Through Nuclear Reaction Rate Measurements and Isotopic Analyses of Stardust

Brett Isselhardt | 20-ERD-030

Project Overview

Microscopic stardust grains, found in trace amounts in primitive meteorites, afford a unique opportunity to study stellar nucleosynthesis in the laboratory by measuring their heavy element isotopic compositions. Applying LLNL's state-of-the art material characterization capabilities to these micrometer-sized grains yields large new datasets with unprecedented precision. However, the astrophysical models necessary to interpret the isotopic record require improved nuclear physics data to constrain stellar nucleosynthesis conditions. For example, the branch point in the s-process path at 95Zr controls the relative amounts of heavier nuclides but is poorly understood. We conducted a coordinated effort across disciplines to combine a new determination of the neutron capture cross section of 95Zr with the laboratory analysis of hundreds of stardust grains to yield a view into stellar interiors. We developed new methods to quantify multiple isotopic systems simultaneously (e.g., Zr, Ba, and W) in stardust grains and improved the determination of the neutron capture cross section of unstable 95Zr via the surrogate reaction method. This interdisciplinary approach is allowing us to fill gaps in our understanding of the environments in which elements are produced while enhancing LLNL's experimental and theoretical capabilities relevant to nuclear threat reduction missions.

Mission Impact

This research supports NNSA, DOE, and LLNL missions in nuclear threat reduction and enhances the Laboratory's Core Competency in nuclear, Chemical, and Isotopic Science and Technology. The work to measure the 95Zr neutron capture cross section via the surrogate method will be applied to improve our understanding of the fundamental nuclear data supporting nuclear deterrence. Additionally, by demonstrating challenging isotopic measurements on microscopic stardust grains, this research demonstrates rapid analyses relevant to NNSA, DOD, and DHS mission goals aimed to reduce analytical timelines and sample consumption. This project strengthens LLNL's international leadership in trace isotopic analyses and helps LLNL establish its capability as a laboratory for analyzing future NASA sample-return material and as a participant in NASA's Emerging Worlds program (research to understand the formation and early evolution of the Solar System). 

Publications, Presentations, and Patents

Awarded 10.9 mg of asteroid Ryugu from the Japan Aerospace Exploration Agency's Hayabusa2 sample-return mission.

Shulaker, D. Z., R. Trappitsch, M. R. Savina, B. H. Isselhardt. 2023. "High-useful yield and new autoionizing state of resonantly ionized Tungsten." Journal of Analytical Atomic Spectrometry, 38(2), 457-463. LLNL-JRNL-840483.

Chimanski, E. V., E. J. In, J. E. Escher, S. Péru, W. Younes. 2022. "Towards a Predictive HFB+ QRPA Framework for Deformed Nuclei: Selected Tools and Technique." Journal of Physics: Conference Series, 2340(1), 012033. IOP Publishing. LLNL-PROC-833788.

Trappitsch, R., D. Z. Shulaker, W. J. Ong, M. W. Savina, B. H. Isselhardt. 2022. "Resonance Ionization of Zirconium." Journal of Radioanalytical and Nuclear Chemistry, 331(12), 5199-5204. LLNL-JRNL-834497.

Lugaro, M., B. Cseh, B. Világos, A. I. Karakas, P. Ventura, F. Dell'Agli, R. Trappitsch et al. 2020. "Origin of large meteoritic SiC stardust grains in metal-rich AGB stars." The Astrophysical Journal, 898(2), 96. LLNL-JRNL-80274.

B. Isselhardt, "From Stardust to Spent Fuel: Deciphering Fingerprints of Neutron Capture by Resonance Ionization Mass Spectrometry" (Presentation, École polytechnique fédérale de Lausanne, Lausanne, Switzerland, Sept 2023). LLNL-PRES-850414.

B. Isselhardt, "Deciphering fingerprints of stellar nucleosynthesis through nuclear reaction rate measurements and isotopic analyses of stardust" (Presentation, 2023 International Conference on Applications of Nuclear Techniques, Crete, Greece, June 2023). LLNL-PRES-850409.

B. Wang, C. Reingold, J. Harke, R. Hughes, J. Escher, S. Burcher, E. Chimanski, J. Koros, B. Longfellow, W. J. Ong, M. R. Savina, D. Z. Shulaker, A. Tamashiro, R. Trappitsch, P. Weber, B. Isselhardt,"Determining the 95Zr(n,g) and 93Zr(n, g) cross sections via 96Zr(p,p') and 94Zr(p,p') surrogate reactions" (Presentation, 2022 APS DNP Meeting, New Orleans, LA, Oct 2022). LLNL-PRES-827881.

Trappitsch, R., W. J. Ong, C. J. Dory, D. Z. Shulaker, M. Lugaro, M. R. Savina, P. Weber, B. H. Isselhardt, S. Amari. "Simultaneous analyses of Titanium and Molybdenum isotopic compositions in presolar SiC grains." Meteoritics & Planetary Science, 56. 111 River St, Hoboken 07030-5774, NJ USA: WILEY. LLNL-PRES-825885.

Pal, I., M. Jadhav, M. R. Savina, D. Z. Shulaker, C. J. Dory, F. Gyngard, N. Kita, and S. Amari. 2022. "Heavy Element Isotopic Measurements of High Density Presolar Graphite Grains with LION." Lunar and Planetary Science Conference, 2678, 1262. LLNL-ABS-830518.

Pal, I., M. Jadhav, M. R. Savina, D. Z. Shulaker, C. J. Dory, F. Gyngard, N. Kita, S. Amari. 2022. "P-nuclide enrichments in presolar graphite grains." Meteoritics & Planetary Science, 57. 111 River St, Hoboken 07030-5774, NJ USA: WILEY. LLNL-ABS-834931.

J.E. Escher, "Static and Dynamic Properties of Medium-Mass and Heavy Nuclei: From Phenomenology to Microscopic Descriptions" (Invited Presentation, DNP 2022 Meeting, Bulletin of the American Physical Society, New Orleans, LA. Oct 2022). LLNL-PRES-849492. 

E. V. Chimanski, "Modern Description of Nuclear Structure and Reactions: The Deformed QRPA Transition Densities for Inelastic Scattering Description" (Contributed to Presentation,15th International Conference on Nuclear Data for Science and Technology, Virtual, 2022). LLNL-PRES-827742.

J.E. Escher, "Improving nuclear data evaluations with predictive reaction theory and indirect measurements" (Presentation, Nuclear Data 2022 Conference, Virtual, July 22-29, 2022). LLNL-PRES-837977.

Wang, B., C. Reingold, J. Harke, R. Hughes, J. Escher, S. Burcher, E. Chimanski, J. Crowhurst, B. H. Isselhardt, W. J. Ong, M. Savina, D. Z. Shulaker, A. Tamashiro, R. Trappitsch, P. Weber. 2021. "Determining the 95Zr(n, g) and 93Zr(n, g) cross sections via 96Zr(p, p') and 94Zr(p, p') surrogate reactions." In APS Division of Nuclear Physics Meeting Abstracts. 2021. MD-007.

J.E. Escher, "Understanding Radionuclides: A Theorist's Perspective" (Invited Presentation, INT Program Radionuclies: Nuclear Physics, Astrophysical Models, and Observations, Seattle, WA, October 4-22, 2021). LLNL-PRES-827744.

E.V. Chimanski, "Modern Inelastic Scattering Descriptions for Nuclear Data Evaluations, Nuclear Structure and Reaction Studies" (Invited Presentation,  the National Nuclear Data Center, Upton, NY, August 2021). LLNL-PRES-825059.

J.E. Escher "Advancing Our Understanding of Nuclear Reactions for Astrophysics and Applications" (Presentation, C2R2 Invited Seminar, South Korea, August 2021). LLNL-PRES-826220. 

W. J. Ong,"Clues to the Origin of the p-nuclei" (Invited Plenary Presentation, Low Energy Community Meeting, Livermore, CA, August 2021). LLNL-PRES-825719.