Advances in Computational Astrophysics: Modeling Planetary Formation and Dynamics
This presentation explores the groundbreaking work in computational astrophysics by James Wadsley and his team, focusing on the numerical modeling of dynamics and evolution of astrophysical systems. Key topics include gravitational physics, hydrodynamics, and radiative transfer. The talk discusses the implementation of advanced N-body solvers and hydrodynamic methods applied to simulating complex phenomena, such as galaxy formation and planet formation mechanisms. Utilizing high-performance computing resources such as the Idra supercomputer, the research addresses intricate astrophysical processes occurring over billions of years.
Advances in Computational Astrophysics: Modeling Planetary Formation and Dynamics
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Presentation Transcript
SHARCNET AGM 2003, Guelph2003 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 • Tools: N-body Solvers, Fluid Dynamics Methods, Adaptive Meshes
Early Simulations… Interacting Galaxies Holmberg 1941 …74 light bulbs and patience
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
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
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
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
Extrasolar Planets: Not like the Solar System DETECTION -> SAMPLE • Over 100 detected: http://exoplanets.org Elliptical Orbits Bigger than Jupiter
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)
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)
Gas Giant Formation Simulation Mayer, Quinn, Wadsley & Stadel, SCIENCE, 2002
