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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qc

p

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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?

• Higher mass “planets”: sharper truncationRice 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…?

GM Aur: 6.5 AU Gap• Inner disk mass ~ 10-8 M

T

1/5

• Low density material in gap “fills in” images• Inner gaps more obvious in SEDs !!

m m m

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