I. Iben (EDT), Alvio Renzini (EDT) Physical Processes in Red Giants

Annotation

In recent years, it has become clear that the red-giant phase is one of the most dramatic periods in a star's life, when all of its parts become involved in ways that have both direct and indirect observational consequences. This is most particularly true of low- and intermediate- mass stars during the second ascent of the giant branch. Such stars bring to their surfaces products of nucleosynthesis currently taking place in their deep interiors, they pulsate as Mira variables, develop extended outward-flowing atmospheres that may exhibit maser properties, and shed great quantities of matter, sometimes highly processed, into the inter- stellar medium. The manner in which processed matter is brought to the surface is far from being completely explained, and the precise mechanism or mechanisms whereby matter is ejected from the stellar surface (whether by deposition of Alfven waves, radiation pressure on grains, or as a consequence of so- me large scale envelope instability) has yet to be elucidated to every- one's satisfaction. The purpose of the second workshop in Astrophysics, organized by the "Advanced School of Astronomy", was to bring together experts on all the physical processes occurring in red giants in an effort to emphasize the interrelatedness of these individual processes, and to encourage a dia- logue among experts that might serve to initiate a synthesis, or at least sharpen our understanding of the most important problems to address in the future.