The study of the ²⁰Ne(p,γ)²¹Na and ²¹Ne(p, γ)²²Na reactions at LUNA

¹ Istituto Nazionale di Fisica Nucleare (INFN) - Sezione di Genova and Università degli Studi di Genova, Via Dodecaneso 33, 16146 Genova, Italy
² School of Physics and Astronomy, University of Edinburgh, EH9 3FD Edinburgh, United Kingdom

^* e-mail: sandra.zavatarelli@ge.infn.it
^** e-mail: ragan.sidhu@ed.ac.uk

Published online: 11 April 2025

Abstract

Among the hydrogen burning processes in stars, proton reactions with Ne isotopes are very relevant to constrain the production and abundances of neon and sodium isotopes in massive stars, novae and supernovae. In particular the ²⁰Ne(p,γ)²¹Na reaction is the first and slowest reaction of the NeNa cycle and it controls the speed at which the entire cycle proceeds: its rate affects the synthesis of all the elements in the cycle. In the temperature range from 0.1 GK to 1 GK, it is dominated by the E_p= 386 keV resonance and by the direct capture component. On the other hand, the ²⁰Ne(p,γ)²¹Na reaction has a relevant role in the production of the radioactive isotope ²²Na in novae and supernovae. At T= 0.1-0.7 GK, the main contributions to the stellar rate are provided by several resonances (E_p=126, 271, 272, 290 and 352 keV). Both reactions have been recently studied at LUNA (Laboratory for Underground Nuclear Astrophysics) using the intense proton beam delivered by the LUNA 400 kV accelerator and a windowless differential-pumping gas target coupled with two high-purity germanium detectors. The contribution is aimed to summarise the new results and to highlight their impact on NeNa cycle.