Nuclear reactions power stars and drive the synthesis of chemical elements in the universe. In explosive astrophysical environments, such as core-collapse supernovae and classical novae, these reactions determine the production of key isotopes and shape the observable chemical composition of stellar remnants. In this seminar, I will discuss the role of nuclear reactions in these environments, focusing on recent experimental and theoretical advances.
First, I will present a new measurement of the ¹³N(α,p)¹⁶O reaction using an intense radioactive ¹³N beam (~1 MHz) and the CRIB setup at RIBF/CNS. This reaction plays a critical role in core-collapse supernova nucleosynthesis, influencing the production of key radioactive isotopes such as ⁴⁴Ti, ⁵⁶Ni, and neutron-rich iron-group elements. However, its reaction rate has remained uncertain due to experimental challenges in producing intense ¹³N beams. Recent sensitivity studies have identified this reaction as a major source of nuclear uncertainty, affecting isotopic yields in supernova remnants and presolar grains [1,2,3,4].
Next, I will discuss a new nuclear reaction sensitivity study for low-metallicity novae [5,6]. Unlike their solar-metallicity counterparts, which primarily synthesize elements up to calcium, low-metallicity novae have been suggested to produce elements up to the copper-zinc region. Understanding the nuclear reaction rates in these environments is essential to refine our models of nova nucleosynthesis. Experimental studies at both stable and radioactive beam facilities are needed to improve reaction rate precision and enhance our understanding of nucleosynthesis in metal-poor stellar environments.
* This work is supported by U.S. Department of Energy, Office of Science, Office of Nuclear Physics, under Award Number DE-SC0017799 and Contract Nos. DE-FG02-97ER41033 and DE-FG02-97ER41042.
References
[1] K. Hermansen et al., Astrophys. J 901, 77 (2020).
[2] S. Subedi et al., Astrophys. J 898, 5 (2020).
[3] A. Meyer et al., Phys. Rev. C 102, 035803 (2020).
[4] H. Jayatissa et al., Phys. Rev. C 105, L042802 (2022)
[5] J. José et al., Astrophys. J 622, L103 (2007).
[6] A. Psaltis et al. (in preparation).
