Nucleosynthesis contributions to the solar nebula

Abstract

The discovery of isotopic anomalies in meteorites suggests that the Solar System is made of material from compositionally different and imperfectly mixed reservoirs. One of them, which comprises the bulk Solar System material, is considered to be made of the well-homogenized ashes of many nucleosynthesis events. Its composition can be studied through models of the chemical evolution of the Galaxy. The main nucleosynthetic agents responsible for that evolution are very briefly reviewed, as well as the level of reliability of the model predictions. The remaining reservoir(s) contain(s) isotopically anomalous material, which probably represents only a very minute fraction of the total Solar System material. The great astrophysical importance of the existence of such reservoirs is emphasized. Some selected examples are given to illustrate the rich diversity of potential nucleosynthetic mechanisms that possibly produced the isotopically anomalous material. The difficulties encountered and uncertainties involved in trying to interpret the array of anomalies within nucleosynthesis models are stressed, as well as the key importance of correlated anomalies.