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Recent improvements in stellar models for intermediate-mass and massive stars are recalled, together with their expectations for the synthesis of radioactive nuclei of lifetime $tau lesssim 25$ Myr, in order to re-examine the origins of now extinct radioactivities, which were alive in the solar nebula. The Galactic inheritance broadly explains most of them, especially if $r$-process nuclei are produced by neutron star merging according to recent models. Instead, $^{26}$Al, $^{41}$Ca, $^{135}$Cs and possibly $^{60}$Fe require nucleosynthesis events close to the solar formation. We outline the persisting difficulties to account for these nuclei by Intermediate Mass Stars (2 $lesssim $ M/M$_odot lesssim 7 - 8$). Models of their final stages now predict the ubiquitous formation of a $^{13}$C reservoir as a neutron capture source; hence, even in presence of $^{26}$Al production from Deep Mixing or Hot Bottom Burning, the ratio $^{26}$Al/$^{107}$Pd remains incompatible with measured data, with a large excess in $^{107}$Pd. This is shown for two recent approaches to Deep Mixing. Even a late contamination by a Massive Star meets problems. In fact, inhomogeneous addition of Supernova debris predicts non-measured excesses on stable isotopes. Revisions invoking specific low-mass supernovae and/or the sequential contamination of the pre-solar molecular cloud might be affected by similar problems, although our conclusions here are weakened by our schematic approach to the addition of SN ejecta. The limited parameter space remaining to be explored for solving this puzzle is discussed.
The abundances of 92Nb and 146Sm in the early Solar System are determined from meteoritic analysis and their stellar production is attributed to the p process. We investigate if their origin from thermonuclear supernovae deriving from the explosion o
Coronal mass ejections (CMEs) were discovered in the early 1970s when space-borne coronagraphs revealed that eruptions of plasma are ejected from the Sun. Today, it is known that the Sun produces eruptive flares, filament eruptions, coronal mass ejec
If the Sun was born in a relatively compact open cluster, it is quite likely that a massive (10MSun) star was nearby when it exploded in a supernova. The repercussions of a supernova can be rather profound, and the current Solar System may still bear
This chapter presents a (partial) review of the information we can derive on the early history of the Solar System from radioactive nuclei of very different half-life, which were recognized to have been present alive in pristine solids. In fact, radi
A critical constraint on solar system formation is the high $^{26}$Al/$^{27}$Al abundance ratio of 5 $times 10^{-5}$ at the time of formation, which was about 17 times higher than the average Galactic ratio, while the $^{60}$Fe/$^{56}$Fe value was ab