Planet Formation in Magnetized Accretion Disks

COFFEE_KLATCH · Invited

Abstract

Stars form by the flow of matter through an accretion disk. Inside these disks, solids particles suspended in the gas grow to form terrestrial planets and giant planet cores. I will review the physical processes of early planet growth, with an emphasis on the strong aerodynamic coupling between gas and dust (as well as larger solids). Turbulence in the gas disk is a crucial issue for these interactions. The magneto rotational instability (MRI) is the leading candidate to drive turbulent momentum transport in disks. I will briefly summarize the current status of MRI turbulence in weakly magnetized circumstellar disks. Then I will describe how MRI turbulence affects the formation of planets. By vigorously mixing small solids, turbulence generally tends to oppose the accumulation into planets. Yet somehow planets form. MRI turbulence has the tendency to support long-lived, axisymmetric zonal flows. These super- and sub-Keplerian flows surround a pressure maximum which efficiently accumulates centimeter to meter scale solids. These solids are further subject to a strong aerodynamic clumping mechanism driven by the streaming instability (Youdin \& Goodman, 2005). Dense clumps of small solids can then collapse gravitationally into 100 km-scale solid planetesimals. Theories of early planet formation are recorded in the asteroid and Kuiper belts of our Solar System, the debris disks surrounding other stars and in magnetized meteorite fragments that fall to Earth.

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Authors

  • Antony Valentini

    CITA, MIT, Caltech/JPL, Academia Sinica, Dong Hwa Univ., Soochow Univ., Nanticoke High School, UT, Maverick Systems Corp., RIS Corp., LSU, Shimadzu Corp., UNIRIB, ORAU/ORISE, Physics Division, Oak Ridge National Laboratory, Oak Ridge Associated Universities, Los Alamos National Laboratory, University of South Dakota, RIKEN BNL Research Center, University of Wisconsin-Milwaukee, Brown University, University of Maryland, Jet Propulsion Laboratory - California Institute of Technology, Center for Relativistic Astrophysics, Georgia Tech, University of Rochester, University of Idaho, Texas A\&M University, Universit\'e Paris Diderot-Paris 7, Washington University in St. Louis, Harvard-Smithsonian Center for Astrophysics, University of California, Berkeley, Massachusetts Institute of Technology, Rockwell Collins Inc., Northwestern University, N IST, Indiana Unviersity, Harvard University, University of Notre Dame, Fachbereich Theoretische Physik, Institut fur Physik, Karl-Franzens-Universitat Graz, Austria, Instituto de Estructura de la Materia, CSIC, Spain, Physics Department, University of Wisconsin-Barron, Orion Foundation, Physics Dept, University of West Florida, Pensacola, Florida, 32514, TUNL, Duke University, James Madison University, University of New Mexico, Photonics CoE, Idaho State University, Pocatello, ID 83209, Los Alamos National Laboratory, Los Alamos, NM 87545, Argonne National Laboratory, University of Washington, National Institute of Standards and Technology, National Institute of Standards and Technology (and West Virginia University), NRAO, University of Florida, LLNL / NPS, LLNL, UC Berkeley, LLNL/NPS, Univerity of Washington, CNRS-IN2P3, Marseille, FR, CERN and King's College, London UK, Brookhaven National Laboratory, ICTP, Trieste, IT, Fermi National Accelerator Laboratory, University of Wisconsin Milwaukee, Princeton University, North Carolina Central U. (NCCU), Triangle Universities Nuclear Laboratory (TUNL), University of California, Riverside, NSCL/MSU, Triangle Universities Nuclear Laboratory, Duke University, University of North Carolina, Duke University, University of North Carolina at Chapel Hill, Triangle Universities Nuclear Laboratory, KVI Groningen, APS Director of Public Affairs, Perimeter Institute, Caltech, Rutgers, U. Tenn., ORNL, Stanford School of Medicine, Radiation Oncology and Molecular Imaging Program, Stanford Applied Physics Department, Stanford School of Medicine, Radiation Oncology, Boston University, BNL, Rutgers University, Purdue University, Penn. State University, UCSD, Lawrence Livermore National Laboratory, University of Richmond, University of Massachusetts-Lowell, Mississippi State University, University of Tennessee, Argonne National Lab, Florida State University, US Naval Academy, ANL, Univ. of Maryland, Univ. of Massachusetts (Lowell), Univ. of Tennessee, Univ. of Manchester, UK, NBI, Danmark, Mississippi State Univ., Physics Division, Argonne National Laboratory, Argonne, IL 60439, Mississippi State University, Mississippi State, MS 39762, UGC-DAE Consortium for Science Research, Kolkata, India, Department of Physics, University of Notre Dame, Notre Dame, IN 46556, San Jose State University, Pacific Northwest National Laboratory, University of Chicago, Fermilab, Program Director, US LHC Accelerator Research Program (LARP), Montana State University, Department of Astrophysical Sciences, Princeton University, School of Mathematics, University of Southampton, CCT, Louisiana State University, CSIC-IEEC Barcelona, TAPIR, California Institute of Technology, University of Texas at Brownsville, Royal Military College of Canada, California State University, Sacramento, Norfolk State University, Oak Ridge National Laboratory, Utah State University, Executive Producer \& Co-Creator of The Big Bang Theory, University of California, Los Angeles, Cyclotron Institute, Texas A\&M University, Hope College, NSCL, Augustana College, Clemson University