Studying Sodium Production in Globular Clusters via the <sup>23</sup>Na(<sup>3</sup>He,d)<sup>24</sup>Mg Reaction
ORAL
Abstract
Globular clusters are dense, gravitationally bound collections of hundreds of thousands of stars. Our theories of stellar evolution, at the present time, cannot account for the observed anticorrelation between sodium and oxygen in cluster stars. While the astrophysical site of these so called abundance anomalies is still unknown, this chemical signature indicates the in situ processing of
stellar material by hydrogen burning at temperatures of 50 - 100 MK. Unfortunately, many key thermonuclear reaction rates suffer from large uncertainties at these temperatures, including the proton induced sodium destroying reactions. Using the Split-pole Spectrograph at Triangle Universities Nuclear Laboratory, we measured the 23Na(3He,d)24Mg transfer reaction. Using first-of-their-kind Bayesian analysis techniques, we have extracted excitation energies and proton partial widths with rigorous uncertainties. Stellar models using our updated values reaffirm the delicate interplay between 23Na(p, γ) and 23Na(p, α) at the temperatures relevant to globular cluster nucleosynthesis.
stellar material by hydrogen burning at temperatures of 50 - 100 MK. Unfortunately, many key thermonuclear reaction rates suffer from large uncertainties at these temperatures, including the proton induced sodium destroying reactions. Using the Split-pole Spectrograph at Triangle Universities Nuclear Laboratory, we measured the 23Na(3He,d)24Mg transfer reaction. Using first-of-their-kind Bayesian analysis techniques, we have extracted excitation energies and proton partial widths with rigorous uncertainties. Stellar models using our updated values reaffirm the delicate interplay between 23Na(p, γ) and 23Na(p, α) at the temperatures relevant to globular cluster nucleosynthesis.
*This material is based upon worksupported by the U.S. Department of Energy, Office of Science,Office of Nuclear Physics, under Award No. DE-SC0017799and Contract No. DE-FG02-97ER41041.
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Presenters
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Caleb A Marshall
- Ohio University
- Ohio University/FRIB
- Institute of Nuclear & Particle Physics, Department of Physics & Astronomy, Ohio University, Athens, Ohio 45701, USA