The production of short-lived radionuclides by new non-rotating and rotating Wolf-Rayet model stars

Abstract

Confext. It has been speculated that WR winds may have contaminated the forming solar system, in particular with short-lived radionuclides (half-lives in the approximate 105-108 y range) that are responsible for a class of isotopic anomalies found in some meteoritic materials. Aims. We revisit the capability of the WR winds to eject these radionuclides using new models of single non-exploding WR stars with metallicity Z = 0.02. Methods. The earlier predictions for non-rotating WR stars are updated, and models for rotating such stars are used for the first time in this context. Results. We find that (1) rotation has no significant influence on the short-lived radionuclide production by neutron capture during the core He-burning phase, and (2) 26Al,36Cl, 41Ca, and 107Pd can be wind-ejected by a variety of WR stars at relative levels that are compatible with the meteoritic analyses for a period of free decay of around 105 y between production and incorporation into the forming solar system solid bodies. Conclusions. We confirm the previously published conclusions that the winds of WR stars have a radionuclide composition that can meet the necessary condition for them to be a possible contaminating agent of the forming solar system. Still, it remains to be demonstrated from detailed models that this is a sufficient condition for these winds to have provided a level of pollution that is compatible with the observations. © ESO 2006.