Search

Over the last three years, the rates of all the main nuclear reactions involving the destruction and production of 26Al in stars (26Al(n, p)26Mg, 26Al(n, α)23Na, 26Al(p, γ)27Si and 25Mg(p, γ)26Al) have been re-evaluated thanks to new high-precision experimental measurements of their crosssections at energies of astrophysical interest, considerably reducing the uncertainties in the nuclear physics affecting their nucleosynthesis. We computed the nucleosynthetic yields ejected by the explosion of a high-mass star (20 M⊙, Z = 0.0134) using the FRANEC stellar code, considering two explosion energies, 1.2 × 1051 erg and 3 × 1051 erg. We quantify the change in the ejected amount of 26Al and other key species that is predicted when the new rate selection is adopted instead of the reaction rates from the STARLIB nuclear library. Additionally, the ratio of our ejected yields of 26Al to those of 14 other short-lived radionuclides (36Cl, 41Ca, 53Mn, 60Fe, 92Nb, 97Tc, 98Tc, 107Pd, 126Sn, 129I, 36Cs, 146Sm, 182Hf, 205Pb) are compared to early solar system isotopic ratios, inferred from meteorite measurements. The total ejected 26Al yields vary by a factor of ~3 when adopting the new rates or the STARLIB rates. Additionally, the new nuclear reaction rates also impact the predicted abundances of short-lived radionuclides in the early solar system relative to 26Al. However, it is not possible to reproduce all the short-lived radionuclide isotopic ratios with our massive star model alone, unless a second stellar source could be invoked, which must have been active in polluting the pristine solar nebula at a similar time of a core-collapse supernova. [ABSTRACT FROM AUTHOR]

Short-lived radioactive isotopes (SLRs) with half-lives between 0.1 and 100 Myr can be used to probe the origin of the Solar system. In this work, we examine the core-collapse supernovae production of the 15 SLRs produced: 26Al, 36Cl, 41Ca, 53Mn, 60Fe, 92Nb, 97Tc, 98Tc, 107Pd, 126Sn, 129I, 135Cs, 146Sm, 182Hf, and 205Pb. We probe the impact of the uncertainties of the core-collapse explosion mechanism by examining a collection of 62 core-collapse models with initial masses of 15, 20, and 25 M⊙, explosion energies between 3.4 × 1050 and 1.8 × 1052 erg and compact remnant masses between 1.5 and 4.89 M⊙. We identify the impact of both explosion energy and remnant mass on the final yields of the SLRs. Isotopes produced within the innermost regions of the star, such as 92Nb and 97Tc, are the most affected by the remnant mass, 92Nb varying by five orders of magnitude. Isotopes synthesized primarily in explosive C-burning and explosive He-burning, such as 60Fe, are most affected by explosion energies. 60Fe increases by two orders of magnitude from the lowest to the highest explosion energy in the 15 M⊙ model. The final yield of each examined SLR is used to compare to literature models. [ABSTRACT FROM AUTHOR]