The bulk of p isotopes is created in the gamma processes mainly by sequences of photodisintegrations and beta decays in explosive conditions in Type Ia supernovae (SNIa) or in core collapse supernovae (ccSN). The contribution of different stellar sou
rces to the observed distribution of p-nuclei in the Solar System is still under debate. We explore single degenerate Type Ia supernovae in the framework of two-dimensional SNIa delayed-detonation explosion models. Travaglio et al. (2011, TRV11) discussed the sensitivity of p-nuclei production to different SNIa models, i.e. delayed detonations of different strength, deflagrations, and the dependence on selected s-process seed distributions. Here we present a detailed study of p-process nucleosynthesis occuring in SNIa with s-process seeds at different metallicities. Based on the delayed-detonation model DDT-a of TRV11, we analyze the dependence of p-nucleosynthesis on the s-seed distribution obtained from different strengths of the 13C-pocket. Using a Galactic chemical evolution code (see Travaglio et al. 2004) we study the contribution of SNIa to the solar stable p-nuclei. We find that explosions of Chandrasekhar-mass single degenerate systems produce a large amount of p-nuclei in our Galaxy, both in the range of light (A < 120) and heavy p-nuclei, at almost flat average production factors (within a factor of about 3). We discussed in details p-isotopes such as 94Mo with a behavior diverging from the average, which we attribute to uncertainties in the nuclear data or in SNIa modelling.
The nucleosynthesis of proton-rich isotopes is calculated for multi-dimensional Chandrasekhar-mass models of Type Ia supernovae with different metallicities. The predicted abundances of the short-lived radioactive isotopes 92Nb, 97Tc, 98Tc and 146Sm
are given in this framework. The abundance seeds are obtained by calculating s-process nucleosynthesis in the material accreted onto a carbon-oxygen white dwarf from a binary companion. A fine grid of s-seeds at different metallicities and 13C-pocket efficiencies is considered. A galactic chemical evolution model is used to predict the contribution of SNIa to the solar system p-nuclei composition measured in meteorites. Nuclear physics uncertainties are critical to determine the role of SNeIa in the production of 92Nb and 146Sm. We find that, if standard Chandrasekhar-mass SNeIa are at least 50% of all SNIa, they are strong candidates for reproducing the radiogenic p-process signature observed in meteorites.
We study the s-process abundances (A > 90) at the epoch of the solar-system formation. AGB yields are computed with an updated neutron capture network and updated initial solar abundances. We confirm our previous results obtained with a Galactic Chem
ical Evolution (GCE) model: (i) as suggested by the s-process spread observed in disk stars and in presolar meteoritic SiC grains, a weighted average of s-process strengths is needed to reproduce the solar s-distribution of isotopes with A > 130; (ii) an additional contribution (of about 25%) is required in order to represent the solar s-process abundances of isotopes from A = 90 to 130. Furthermore, we investigate the effect of different internal structures of the 13C-pocket, which may affect the efficiency of the 13C(a, n)16O reaction, the major neutron source of the s-process. First, keeping the same 13C profile adopted so far, we modify by a factor of two the mass involved in the pocket; second, we assume a flat 13C profile in the pocket, and we test again the effects of the variation of the mass of the pocket. We find that GCE s-predictions at the epoch of the solar-system formation marginally depend on the size and shape of the 13C-pocket once a different weighted range of 13C-pocket strengths is assumed. We ascertain that, independently of the internal structure of the 13C-pocket, the missing solar-system s-process contribution in the range from A = 90 to 130 remains essentially the same.
We study the s-process abundances at the epoch of the Solar-system formation as the outcome of nucleosynthesis occurring in AGB stars of various masses and metallicities. The calculations have been performed with the Galactic chemical evolution (GCE)
model presented by Travaglio et al. (1999, 2004). With respect to previous works, we used updated solar meteoritic abundances, a neutron capture cross section network that includes the most recent measurements, and we implemented the $s$-process yields with an extended range of AGB initial masses. The new set of AGB yields includes a new evaluation of the 22Ne(alpha, n)25Mg rate, which takes into account the most recent experimental information.
We explore SNIa as p-process sources in the framework of two-dimensional SNIa models using enhanced s-seed distributions as directly obtained from a sequence of thermal pulse instabilities. The SNIa WD precursor is assumed to have reached the Chandra
sekhar mass limit in a binary system by mass accretion from a giant/main sequence companion. We apply the tracer-particle method to reconstruct the nucleosynthesis from the thermal histories of Lagrangian particles, passively advected in the hydrodynamic calculations. For each particle we follow the explosive nucleosynthesis with a detailed nuclear reaction network. We select tracers within the typical temperature range for p-process production, 1.5-3.7 109K, and analyse in detail their behaviour, exploring the influence of different s-process distributions on the p-process nucleosynthesis. We find that SNIa contribute to a large fraction of p-nuclei, both the light p-nuclei and the heavy-p nuclei at a quite flat average production factor. For the first time, the very abundant Ru and Mo p-isotopes are reproduced at the same level as the heavy p-nuclei. We investigate the metallicity effect on the p-process production. Starting with a range of s-seeds distributions obtained for different metallicities, running SNIa two-dimensional models and using a simple chemical evolution code, we give estimates of the SNIa contribution to the solar p-process composition. We find that SNIa contribute for at least 50% at the solar p-nuclei composition, in a primary way.
