Monte Carlo Radiation Transfer in Protoplanetary Disks:
Disk-Planet Interactions
Kenneth Wood
St Andrews
Radiation Transfer + Hydrodynamics
RT Models: Barbara Whitney, Jon Bjorkman, Christina Walker, Mark O’Sullivan
Dust Theory: Mike Wolff
SPH Models: Ken Rice, Mike Truss, Ian Bonnell
Observations: Rachel Akeson, Charlie Lada, Ed Churchwell, Glenn Schneider, Angela Cotera, Keivan Stassun
Monte Carlo Development History• Scattered light disks &
envelopes (1992)• 3D geometry &
illumination (1996)
• Dust radiative equilibrium (2001)SEDs disks + envelopes
• Monte Carlo for disk surface + diffusion for interior (2002)
• Density grids from SPH simulations (2003)• Spatial variation of dust opacity (2003)• Self consistent vertical hydrostatic equilibrium (2004)
1992: Predictions 1996: HST data
GM Aur: 4AU gap, disk-planet interaction
Disk Structure Calculations
• Our models used parameterized disks: power laws for (r), h(r)
• Disk theory: reduce model parameter space• Irradiated accretion disks: ~ r -1, h ~ r 1.25
(D’Alessio, Calvet, & collaborators)• New Monte Carlo: iterate for disk structure
(Walker et al. 2004)• Model disk-planet interactions in GM Aur
Disk-Planet Interactions: Gap Clearing
Papaloizou, Lin, Bodenheimer, Lubow,
Artymowicz, Nelson, D’Angelo, Kley, …
Simulation from Ken Rice & Phil Armitage
• Observational signatures: images, SEDs?
Protoplanetary Disks• Need high resolution imaging: ALMA
• Gap clearing simulation images:
700m 700m ALMA simulation
Wolf et al. 2002
Inner Gaps from SED Modeling• Remove inner disk material: redistribute near-IR
excess emission to longer s
Rin = 7R*
Rin = 4 AU
GM Aur
See also: Dullemond, et al.Calvet, D’Alessio
Rice et al. (2003)
Estimating Rin from SEDs
• Hot inner edge emits in IR • Include inner edge emission when estimating Rin
6 AU 20 AU 300 AU
T
1/5
GM Aur
Monte Carlo, Rin = 4 AU, i = 0 - 50CG97, Rin = 0.1 AUCG97, Rin = 4 AU
Vertical Hydrostatic Equilibrium
GM Aur
Disk Dust: Grain GrowthISMDisk dust
Dust Size Distribution:Power law + exponential decayGrain sizes in excess of 50mGrayer opacity compared to ISM
Fits HH30, GM Aur, AA Tau, …
Opacity slopes: Dust model: sub-mm ~ B/K ~ 2.5Beckwith & Sargent (1991): sub-mm continuum SEDs: ~
Watson & Stapelfeldt (2004): HH 30 IRS: B/K ~ 1.5 – 4.5
m506.05.3
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c
qc
p
aqp
aaaan
GM Aur: Disk/Planet Interaction?
• NICMOS coronagraph
• Scattered light modeling:
• Mdisk ~ 0.04 M; Rdisk ~ 300 AU; i ~ 50
Schneider et al. 2003
1200 AU
GM Aur: Disk/Planet Interaction?
• Tiny near-IR excess: inner hole first suggested by Koerner, Sargent, & Beckwith (1993)
• SED model requires 4AU gap: planet?
GM Aur: Disk/Planet Interaction?
• 3D SPH calculation from Ken Rice
• Planet at 2.5AU clears inner 4AU in ~2000 yr
Rice et al. 2003
GM Aur: Disk/Planet Interaction?
• Spitzer SED can discriminate “planet” mass
• Centroid shifting ~ 0.1mas: Keck, SIM?
Rice et al. 2003
Mp = 2MJ Mp = 50MJ
More Disks with Gaps
• IRTF: Bergin, Calvet, Sitko, et al. (2004)
• Gap sizes: 3 AU < Rgap < 7 AU
• Silicate emission: smaller grains in inner disk• Sharp truncation, very low density inner disks
GM Aur TW HyaLk Ca 15DM Tau
GM Aur: 6.5 AU Gap• SED model requires low density material in cleared region
• Inner disk mass ~ 10-8 M
• High resolution imaging of inner holes…?
Summary & Future Research• Monte Carlo: self-consistent disk structure calculations• GM Aur: Disk-planet interaction, need mid-IR data• Direct imaging of inner gaps: low density material
“fills in” surface brightness => SEDs find gaps!• Coding: Radiation pressure
Include gas opacityTransiently heated grains
• Goal: merge radiation transfer & hydro• Codes now available at:
http://gemelli.spacescience.org/~bwhitney/codes