Uncertainties in the production of p nuclides in thermonuclear supernovae determined by Monte Carlo variations

Abstract

Thermonuclear supernovae originating from the explosion of a white dwarf accreting mass from a companion star have been suggested as a site for the production of p nuclides. Such nuclei are produced during the explosion, in layers enriched with seed nuclei coming from prior strong s processing. These seeds are transformed into protonricher isotopes mainly by photodisintegration reactions. Several thousand trajectories from a 2D explosion model were used in a Monte Carlo approach. Temperaturedependent uncertainties were assigned individually to thousands of rates varied simultaneously in post-processing in an extended nuclear reaction network. The uncertainties in the final nuclear abundances originating from uncertainties in the astrophysical reaction rates were determined. In addition to the 35 classical p nuclides, abundance uncertainties were also determined for the radioactive nuclides ), important for Galactic Chemical Evolution studies. Uncertainties found were generally lower than a factor of 2, although most nucleosynthesis flows mainly involve predicted rates with larger uncertainties. The main contribution to the total uncertainties comes from a group of trajectories with high peak density originating from the interior of the exploding white dwarf. The distinction between low-density and high-density trajectories allows more general conclusions to be drawn, also applicable to other simulations of white dwarf explosions.

Cross section of α -induced reactions on Au197 at sub-Coulomb energies

“…From Eqs. (5) and (6), the following properties of the reactions under study can be expected. The total reaction cross section σ reac (summed over all non-elastic channels) depends only on the transmission T α,0 in the entrance channel and is thus only sensitive to the chosen α-nucleus optical model potential (A-OMP).…”

Uncertainties in νp-process nucleosynthesis from Monte Carlo variation of reaction rates

“…3. The standard rate set and the assigned uncertainties were the same as previously used in our works (Rauscher et al 2016;Nishimura et al 2017Nishimura et al , 2018Cescutti et al 2018): rates for neutron-, proton-, and α-induced reactions were a combination of theoretical values by Rauscher & Thielemann (2000), supplemented by experimental rates taken from Dillmann et al (2006) and Cyburt et al (2010). Decays and electron captures were taken from a REACLIB file compiled by Freiburghaus & Rauscher (1999) and supplemented by rates from Takahashi & Yokoi (1987) and Goriely (1999) as provided by Aikawa et al (2005) and Xu et al (2013).…”

Determination of the photodisintegration reaction rates involving charged particles: Systematic calculations and proposed measurements based on the facility for Extreme Light Infrastructure–Nuclear Physics

“…Therefore, it is critical to identify the key photodisintegration reactions in the pprocess nucleosynthesis, especially the (γ,p) and (γ,α) reactions, that need prioritizing for the experimentally study. Recently, the uncertainties of the p-nuclei production originated by the variations of the astrophysical reaction rates are systematically studied, using the state-of-the-art Monte Carlo procedure [11,12], and the important reactions for determining the abundance of the p-nuclei are identified. In the present study, the key reactions of (γ,p) and (γ,α) identified by Refs.…”

“…In the present study, the key reactions of (γ,p) and (γ,α) identified by Refs. [11,12] are initially considered as the candidates of the photonuclear measurement. Furthermore, by explicitly checking the half-live of the nuclei involved in these candidate reactions, it is found that many of them cannot be experimentally studied via the photonuclear channel, due to the unavailability of the radiative targets.…”