Hydrogen Burning of 17-O in Classical Novae

A. Chafa, V. Tatischeff, P. Aguer, S. Barhoumi, A. Coc, F. Garrido, M. Hernanz, J. Jose, J. Kiener, A. Lefebvre-Schuhl, S. Ouichaoui, N. de Sereville, J. -P. Thibaud

Published 2005-06-21Version 1

We report on the observation of a previously unknown resonance at E=194.1+/-0.6 keV (lab) in the 17-O(p,alpha)14-N reaction, with a measured resonance strength omega_gamma(p,alpha)=1.6+/-0.2 meV. We studied in the same experiment the 17-O(p,gamma)18-F reaction by an activation method and the resonance-strength ratio was found to be omega_gamma(p,alpha)/omega_gamma(p,gamma)=470+/-50. The corresponding excitation energy in the 18-F compound nucleus was determined to be 5789.8+/-0.3 keV by gamma-ray measurements using the 14-N(alpha,gamma)18-F reaction. These new resonance properties have important consequences for 17-O nucleosynthesis and gamma-ray astronomy of classical novae.