Sketch of the model described in Sect. 2. Star generations #1, #2, and #3 are respectively in red, blue, and green. In panel b), SNe remnants are shown with a dark contour. The reddish background symbolizes ⁶⁰Fe delivered by the SNe belonging to the first star generation. In panel c), the purple color of the shell symbolizes the combination of ²⁶Al delivered by the single massive star wind from generation #2 and the ⁶⁰Fe delivered by generation #1 stars. Our Sun, born in the circumstellar shell together with a few hundreds fellow low-mass stars (generation #3), is shown in yellow.