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Computational Astrophysics: Building Planets

SHARCNET AGM 2003, Guelph 2003. Computational Astrophysics: Building Planets. James Wadsley. Computational Astrophysics. Numerical modeling of dynamics and evolution of astrophysical systems Physics: Gravity, Hydrodynamics, Magnetic Fields, Radiative Transfer, Atomic Chemistry

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Computational Astrophysics: Building Planets

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  1. SHARCNET AGM 2003, Guelph2003 Computational Astrophysics: Building Planets James Wadsley

  2. Computational Astrophysics • Numerical modeling of dynamics and evolution of astrophysical systems • Physics: Gravity, Hydrodynamics, Magnetic Fields, Radiative Transfer, Atomic Chemistry • Tools: N-body Solvers, Fluid Dynamics Methods, Adaptive Meshes

  3. Early Simulations… Interacting Galaxies Holmberg 1941 …74 light bulbs and patience

  4. And then there was SHARCNET… • 270,000,000 particles • 1.3 Billion Lightyear cube • 13 Billion Years Real Time • 11 CPU Years PARALLEL Computer Time • 1 month on Idra Supercomputer (SHARCNET@McMaster) Cosmic Microwave Background, Sunyaev-Zel’dovich Effect Wadsley, Bond, et al. 2002

  5. Ingenuity vs. Moore’s Law Algorithms: • O(N2) Direct N-body • O(N log2 N) Tree • O(N) Hydro O(N2) O(N log2 N) Time Adaptivity Lake 2001

  6. N-body Solver (Tree Method) and Smoothed Particle Hydrodynamics • Parallel, adaptive in space and time • Physics: Gravity, Hydrodynamics, Atomic Chemistry (Radiative Heating, Cooling) • Subgrid Physics: Star Formation, Supernova Feedback, Planetesimal Collisions Wadsley, Stadel & Quinn 2003

  7. Applications Disk Galaxy Formation Governato, Mayer, Wadsley, et al. 2003 Cosmic Microwave Background, Sunyaev-Zel’dovich Effect Wadsley, Bond, et al. 2002 Intracluster light Willman, Governato, Wadsley, et al. Tidal Stirring of Dwarf Galaxies Mayer et al. 2001 Gas Giant Planets Mayer, Quinn, Wadsley & Stadel 2002 Galaxy Cluster X-ray-Temperature Relation Borgani, Governato, Wadsley, et al. 2001,2002

  8. Planets: The Solar System

  9. Extrasolar Planets: Not like the Solar System DETECTION -> SAMPLE • Over 100 detected: http://exoplanets.org Elliptical Orbits Bigger than Jupiter

  10. Star Forming Regions

  11. Planet Formation Mechanisms:1) Planetesimal Accretion • Dust grains/ices settle and agglomerate up to 1 km size • 1 km size bodies gravitationally focus, collide & perturb each other: Runaway Growth to embryo size (~0.1 MEARTH ) • Embryos collide/merge – slow process • ~100 Myr years for Jupiter (Lissauer 1993) • 10 MEARTH objects can accrete gas • Does Jupiter have a core this large? (Guillot et al. 1999)

  12. Planet Formation Mechanisms:2) Dynamical Instabilities • Outer Solar System was cold: Potentially unstable to gravitational fragmentation on dynamical (orbital) timescales • Inner Solar System was hot: Keep the Planetesimal mechanism Temperature vs. Radius (from Boss 2001)

  13. Gas Giant Formation Simulation Mayer, Quinn, Wadsley & Stadel, SCIENCE, 2002

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