Study of astrophysically important resonant states in 30S using the 32S(p,t)30S reaction

Kiana Setoodehnia, McMaster University
Alan A. Chen, McMaster University
Jason A. Clark, Yale University
Catherine M. Deibel, Yale University
David Kahl, McMaster University
Peter D. Parker, Yale University
Christopher Wrede, Yale University


A small fraction (< 1%) of presolar SiC grains is suggested to have been formed in the ejecta of classical novae. The 29P(p,γ) 30S reaction plays an important role in understanding the Si isotopic abundances in such grains, which in turn provide us with information on the nature of the probable white dwarf progenitor's core, as well as the peak temperatures achieved during nova outbursts. This rate is determined by two low-lying 3+ and 2+ resonances above the proton threshold in 30S at 4399 keV. Despite several experimental studies in the past however, the 3+ resonance has only been recently observed in one experiment and no definitive evidence for the 2+ state has been published yet. We have studied the 30S nuclear structure via the 32S(p,t)30S reaction at 5 laboratory angles between 9° to 62°. We have observed between 8 to 14 states above the proton threshold including two levels at 4695.5 γ3.5 keV and 4814.9 γ3.5 keV that are candidates for the 3+ and previously "missing" 2 + state, respectively. © Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlikeLicence.