Modelling Protoplanetary Accretion Discs

1
Modelling Protoplanetary Accretion Discs

• Owen Matthews - Paul Scherrer Institut

Kaspar Arzner Paul Scherrer Institut Laure
Fouchet ETH Mike Truss St Andrews, UK Roland
Speith Tübingen, Germany Graham Wynn
Leicester, UK Daniel Price Exeter, UK Mahendra
Verma Indian Institute of Technology
Planet Z Jamboree - 17th November 2005
2
Accretion Discs Why?

• Discs form stars
• Source of viscosity is uncertain
  (Magneto-rotational instability?)
• Influence of stellar magnetic field unclear

3
Accretion Discs Why?

• Discs form stars
• Source of viscosity is uncertain
  (Magneto-rotational instability?)
• Influence of stellar magnetic field unclear
• Circumstellar discs form planets
• Disc profile and evolution affects where and
  when planets can form
• Disc structure controls planet migration
• Disc composition affects planetary makeup

4
Accretion Discs Why?

• Discs form stars
• Source of viscosity is uncertain
  (Magneto-rotational instability?)
• Influence of stellar magnetic field unclear
• Circumstellar discs form planets
• Disc profile and evolution affects where and
  when planets can form
• Disc structure controls planet migration
• Disc composition affects planetary makeup
• Discs undergo outbursts not just young stars
• Mechanism for brightening not certain
• Timescales not as expected

5
Accretion Discs How?

• Smoothed Particle Hydrodynamics
  A Lagrangian particle method
• Conserves angular momentum and energy
• Resolves high density regions best
• BUT
• Magnetic fields are very tricky!
• (But you can play some games)

6
Accretion Discs How?

• Smoothed Particle Hydrodynamics
  A Lagrangian particle method
• Conserves angular momentum and energy
• Resolves high density regions best
• BUT
• Magnetic fields are very tricky!
• (But you can play some games)

7
Accretion Discs How?

• Smoothed Particle Hydrodynamics
  A Lagrangian particle method
• Conserves angular momentum and energy
• Resolves high density regions best
• BUT
• Magnetic fields are very tricky!
• (But you can play some games)

• Eulerian Grid Based MHD Code (Eg, Flash -
  University of Chicago)
• Magnetic fields can be done
• Adaptive mesh refinement can be done
• BUT
• Does not conserve angular momentum!
• (Depending on grid)

8
Accretion Discs How?

• Eulerian Grid Based MHD Code (Eg, Flash -
  University of Chicago)
• Magnetic fields can be done
• Adaptive mesh refinement can be done
• BUT
• Does not conserve angular momentum!
• (Depending on grid)

9
Accretion Discs How?

• Smoothed Particle Hydrodynamics
  A Lagrangian particle method
• Conserves angular momentum and energy
• Resolves high density regions best
• BUT
• Magnetic fields are very tricky!
• (But you can play some games)

• Eulerian Grid Based MHD Code (Eg, Flash -
  University of Chicago)
• Magnetic fields can be done
• Adaptive mesh refinement can be done
• BUT
• Does not conserve angular momentum!