Hydrogen Burning of $^{17}$O in Classical Novae

A. Chafa , V. Tatischeff (1) , P. Aguer (2) , S. Barhoumi , A. Coc (1) , F. Garrido (1) , M. Hernanz , J. Jose , J. Kiener (1) , A. Lefebvre-Schuhl (1) , S. Ouichaoui , N. de Sereville (1) , J. -P. Thibaud (1)

1 CSNSM - Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse
2 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan

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.

Mots clés: proton-nucleus reactions; proton radiative capture; alpha particle-nucleus reactions; novae; nuclear energy level transitions; nucleosynthesis

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Physique Nucléaire Expérimentale [nucl-ex]; Astrophysique [astro-ph]

A. Chafa, V. Tatischeff, P. Aguer, S. Barhoumi, A. Coc, et al.. Hydrogen Burning of $^{17}$O in Classical Novae. Physical Review Letters, 2005, 95, 031101 (4 p.). ⟨10.1103/PhysRevLett.95.031101⟩. ⟨in2p3-00024492⟩