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Nucleosynthesis and stellar modeling of AGB stars

COFFEE_KLATCH · Invited

Abstract

The last brief phase of nuclear burning for low to intermediate mass stars is the Asymptotic Giant Branch (AGB). It is during the AGB that the richest nucleosynthesis occurs, driven by thermal instabilities of the helium-burning shell, the products of which are dredged to the stellar surface by recurrent mixing episodes. Envelope burning occurs in the most massive AGB stars, also altering the surface composition. The AGB phase is terminated when rapid, episodic mass loss expels the envelope into the interstellar medium, making these stars important contributors to the chemical evolution of galaxies and stellar systems. We review current issues and recent developments in the evolution and nucleosynthesis of AGB stars. We begin with a brief introduction to the topic, followed by an outline of the regions and time-scales for the various important nuclear reactions that occur in these stars. Then we focus on the different numerical approaches adopted in modeling this brief evolutionary phase (parametric, detailed models) with a special emphasis on the associated nucleosynthesis. We will discuss recent efforts to understand the effect that convection, mass loss and reaction rate uncertainties have on the nucleosynthesis, and the role that AGB stars plays in the chemical evolution of the Galaxy.

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Authors

  • Raffaella De Vita

    Kent State University, Jefferson Lab, Ohio University, Mainz University, Mainz, Germany, Max-Planck-Institute for Nuclear Physics, Heidelberg, Germany, University of Washington, Noncommercial Partnership ``Scientific Instruments,'' Moscow, Russia, Lucent Technologies, North-West Technical University, St. Petersburg, Russia, Indiana University-Purdue University Indianapolis, Purdue University, University of Florida, Wabash College and Purdue University, University of Oregon, Garnett McKeen Lab, Inc., Korea Research Institute of Standards and Science, Daejeon, South Korea, 305-600, Department of Physics, Lab. of Solid State Microstructure, Nanjing University, Nanjing, 200008, China, Department of Physics, Hampton University, Hampton, VA 23668, NESB, NASA Langley Research Center, Hampton, VA 23681, Korea Research Institute of Stardards and Science, Daejeon, South Korea, 305-600, Department of Chemical Engineering, Sogang University, South Korea, 121-742, Indiana University, University of Chicago, LBNL, BNL/NSLS, KEK, Fermi National Accelerator Laboratory, LANL, University of Maryland, NIST, HMI, Harvard University, NCSU, Department of Physics and Astronomy, University of Nebraska, University of Southern California, University of California at Los Angeles, Stanford Linear Accelerator Center, Institute for Advanced Physics, Konkuk University, Korea, SUNY College at Oneonta, Department of Physics, University of Wisconsin-Whitewater, Whitewater WI 53190, Cyclotron Institute, Texas A\&M University, College Station, TX, University of Texas at El Paso, University of Buenos Aires, Cyclotron Institute, Texas A\&M University, College Station, TX 77843, Simon Bolivar University, Caracas, Venezuela, Warsaw University, Warsaw, Poland, Institut de Recherches Subatomiques, Strasbourg, France, Florida State University, Harvard-Smithsonian CfA, CENPA University of Washington, Pasadena City College, California State University, Northridge, California State University, Dominguez Hills, Chinese University of Hong Kong, Jet Propulsion Lab, California Institute of Technology, University of California, Irvine, Instituto de F\'isica, UNAM, University of Toronto, Friedrich-Schiller-Universitaet Jena, Pennsylvania State University, NIH, Stanford University, CNR, Italy, University of Texas, Austin, University of Nevada, Reno, University of Wisconsin-Madison, Hanseo University, Division of Materials Science and Technology, KIST, Seoul, 130-791, Korea, Department of Physics, Kangwon National University, Chuncheon, 200-701, Korea, Department of Techno-marketing, Mokwon University, Taejeon, 301-729, Korea, Institute of Physics and Applied Physics, Yonsei University, Seoul, 120-749, Korea, UNAM, Mexico, JINR, Dubna, Univ. of Notre-Dame, ANL, SUNY at Stony Brook, Lund U., ORNL, Washington U., Warsaw, Poland, Saclay, France, Boston University, National Institute for Standards and Technology, Boulder, Los Alamos National Laboratory, Yale University, Florida International University, MIT, Saint Mary's University, TRI-University Meson Facility, Institute of Nuclear Physics, Prague, Czech Republic, Institute of Physics and Nuclear Engineering, Bucharest, Romania, Cyclotron Institute, Texas A\&M Univ., Physics Division, Argonne National Laboratory, Wright Nuclear Structure Laboratory, Yale University, Tenn. Tech. Univ., Arizona State Univ., Ohio Univ., Tennessee Technologival Univ., ORNL Physics Division, Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, University of California, CEA, LLNL, Penn State Altoona, NC A&T State University, TUNL, NASA Langley Research Center, University of Iowa, UMD \& NASA/GSFC, NRC \& NASA/GSFC, NASA/GSFC, Academy at UAH, Oak Ridge National Laboratory, North Carolina State University, Union College, University of Hamburg, Iowa State University, Drake University, Lawrence Livermore National Laboratory, University of Arizona, UNC, Chapel Hill, NC, Tennessee Tech., Cookeville, TN, Rutgers Univ., New Brunswick, NJ, ORNL, Oak Ridge, TN, ORAU, Oak Ridge, TN, Collegium of Natural Sciences, Eckerd College, RIKEN (Institute of Physical and Chemical Research), Department of Physics, Rikkyo University, Department of Physics, University of Tokyo, Department of Physics and Astronomy and National Superconducting Cyclotron Laboratory, Michigan State University, Tokyo Inst. of Tech., Rikkyo Univ., Univ. of Tokyo, RIKEN, NSCL, Michigan State University, Dept. of Physics, University of Surrey, Guildford, UK, National Superconducting Cyclotron Laboratory, Michigan State University, University of Surrey, UK, IRES CNRS Strasbourg, Planetary Science Institute, Steward Observatory, University of Oklahoma, Vatican Observatory, University of Rochester, UIUC, Washington State University, Johns Hopkins University, Istituto Nazionale di Fisica Nucleare-Genova