The production of s-isotopes due to the operation of the reaction 13C(α, n)16O in low-mass stars during asymptotic giant branch phases is investigated following in detail the time evolution of the thermal pulses, the temperature and density stratification within the convective shells, and taking into account the effect of the neutron recycling by 12C through the chain 12C(n, γ)13C(α, n)16O. The resulting average neutron density reaches a maximum of about 5×109cm-3 and then decreases smoothly. Strong overabundances for all s-isotopes with A > 80 are obtained in a solar system distribution. The process appears suitable to reproduce many observed details concerning isotopic ratios.
On the Role of Low-Mass Asymptotic Giant Branch Stars in Producing a Solar System Distribution of s-Process Isotopes
BUSSO, Maurizio MariaInvestigation
;
1988
Abstract
The production of s-isotopes due to the operation of the reaction 13C(α, n)16O in low-mass stars during asymptotic giant branch phases is investigated following in detail the time evolution of the thermal pulses, the temperature and density stratification within the convective shells, and taking into account the effect of the neutron recycling by 12C through the chain 12C(n, γ)13C(α, n)16O. The resulting average neutron density reaches a maximum of about 5×109cm-3 and then decreases smoothly. Strong overabundances for all s-isotopes with A > 80 are obtained in a solar system distribution. The process appears suitable to reproduce many observed details concerning isotopic ratios.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
