Atomic Diffusion in Stars

The authors give an overview of atomic diffusion as applied to all types of stars, showing where it plays an essential role and how it can be implemented in modelling. Part I describes the tools that are required to include atomic diffusion in models of stellar interiors and atmospheres. An important role is played by the gradient of partial radiative pressure, or radiative acceleration, which is usually neglected in stellar evolution. In Part II, the authors systematically review the contribution of atomic diffusion to each evolutionary step. The dominant effects of atomic diffusion are accompanied by more subtle effects on a large number of structural properties throughout evolution. The goal of this book is to provide the means for the astrophysicist or graduate student to evaluate the importance of atomic diffusion in a given star. A fundamental physical process, atomic diffusion can significantly affect the superficial abundances of stars and/or their evolution. This guide includes all the information needed to take proper account of atomic diffusion's impact.

Preface.- Observational Motivation and Brief History.- Part I: Physics of Transport Processes.- Atomic Transport: Diffusion Equations.- Radiative Accelerations.- Transport Coefficients.- Diffusion in Magnetic Fields.- Light Induced Drift.- Macroscopic Transport Processes.- Part II: Abundance Anomalies in Stellar Evolution.- Upper Main Sequence Stars of Pop I.- Lower Main Sequence Stars of Pop I.- Population II Dwarfs.- Giants.- Horizontal-Branch Stars.- White Dwarfs.- Neutron Stars.- Part III: Appendices.- Evaluation of Collision Integrals.- Definition of the linlog Function.- List of Astronomical Objects.- References.- Index.

Prof. Georges Michaud has been a Professeur Émérite at the Université de Montréal since 2005. He has worked in their physics department as a professor since 1969, after obtaining his PhD in astronomy from the California Institute of Technology. He is the recipient of the 2006 C.S. Beals Award from the Canadian Astronomical Society and has been a member of the Royal Society of Canada since 1992. He was awarded the  Steacie Prize of the NRC of Canada in 1980 and the Médaille Janssen  of the Académie des sciences de Paris in 1982.

Dr. Georges Alecian is a CNRS Research Director Emeritus at CNRS-Observatoire de Paris (LUTH). His main fields of research are stellar physics, theory and modeling of transport processes of elements and atomic diffusion. He was director of Laboratory/Department (LAEC/DAEC, CNRS-Observatoire de Paris, Université Paris-Diderot) from 1996 to 2001, and he has been member of the CoRoT space mission scientific council since 1998.  Since 2012, he is foreign member of the National Academy of Sciences of the Republic of Armenia (NAS RA).

Dr. Jacques Richer obtained his PhD in astrophysics from the Université de Montréal in 1993, and has been a research assistant in the physics department’s astronomy group since then. He has also been a scientific computing analyst and consultant with various Québec academic organizations (CERCA, RQCHP, and finally, Calcul Québec) from 1997 to 2015.

His main research activities include numerical simulation of element diffusion inside evolving stars, with emphasis on the role of radiative forces, turbulence mixing and stellar winds.