Abstract :
Thermonuclear runaways are at the origin of some of the most energetic and frequent stellar cataclysmic events. In this paper, we review our understanding of the mechanisms leading to classical nova explosions and x-ray bursts, together with their associated nu- cleosynthesis. In particular, we focus on the interplay between nova outbursts and the Galactic chemical abundances (mainly 13C, 15N, and 17O), the synthesis of radioactive nuclei of interest for gamma-ray astronomy (7Be-7Li, 22Na, or 26Al), the endpoint of nova nucleosynthesis, based both on theoretical and observational grounds, and the recent discovery of presolar meteoritic grains, both in the Murchison and Acfer 094 meteorites, likely condensed in nova shells. Recent progress in the modeling of x-ray bursts as well as an insight into the nuclear uncertainties affecting critical reactions, for both novae and x-ray bursts, are also reviewed.
