Structure & Evolution of Protoplanetary Disks:

Merging 3D Radiation Transfer & Hydrodynamics

Kenneth Wood

St Andrews

Data: Imaging polarimetryPhotometric monitoringScattered light imagesSpectral energy distributions (SEDs)

Theory: Dynamical models of star formation: Collapsing clouds, jets, accretion disks, debris disks, & planet formation

RT Models: 3D Monte Carlo techniques

Data TheoryRadiation Transfer Models& Observational Signatures

Friends & Collaborators

RT Models & Dust Theory: Barbara Whitney, Jon Bjorkman, Mike Wolff

Dynamical Models: Ken Rice, Ian Bonnell, Phil Armitage, Matthew Bate, Scott Kenyon, Adam Frank

Observations: Charlie Lada, Ed Churchwell, Anneila Sargent, Glenn Schneider, Angela Cotera, Debbie Padgett, Keivan Stassun

Monte Carlo Capabilities• 3D geometry & illumination

• Incorporate MHD density & velocity grids

• Scattered light images (optical & infrared)

• Radiative equilibrium dust temperatures

• SEDs & thermal imaging (mid-IR, sub-mm)

Star Formation Theory

yr/10~

AU100~

yr10~

8

6

MM

R

t

d

yr/10~

AU10~

10~

6

3

5

MM

R

yrt

Class 0 Class I Class II

yr/10~

AU10~

10~

5

4

4

MM

R

yrt

Star Formation: Observations

1 100010 100(m)1 100010 1001 100010 100

F

Bourke 2001

Padgett et al. 1999 Krist et al. 2000

BHR71 TW HydraeIRAS 04302+2247

“0” “I” “II”

Near-IR HST Images

Disks, Disks, Disks…

T Tauri Accretion Disks: Images• Disk density: hydrostatic flared disk: h / r = cs(r) / (r) • Shakara & Sunyaev (1973), Lynden-Bell & Pringle (1974)• Direct starlight 10,000 brighter than scattered light from disk• Best detected when star occulted by edge-on flaring disk

Whitney & Hartmann 1992

i = 25 i = 75 i = 85

400

AU

T Tauri Accretion Disks: SEDs• Pole-on: Large IR excess• Edge-on: Double peaked SED: scattered light + thermal

Wood et al. 2002

Star Formation in Taurus

© Steve Kohle & Till Credner, AlltheSky.com

L1551 Region

Whitney, Gomez, & Kenyon (Mt Hopkins, 48”)

Red = [S II]White = Visual

L1551 IRS5HL TauXZ TauHH 30HH 30 IRS

1’ = 8400AU

HH 30 IRS Accretion Disk

Burrows et al. 1996

HST WFPC2:

Green: F555W (V Band)

Red: F617N (H, S[II])

Scattered light models:Assume ISM dust opacityImage morphology: disk geometry, inclinationWidth of dust lane: optical depth, disk mass

yrMM /105.3~ 9jets

Bacciotti et al. 1999

HH 30 IRS: Disk Geometry

HST WFPC2 Model

MMh

rr

rrhrh

zr

d4

1

2

10AU15)AU100(

~)(25.225.1

~)(;)(2

1exp~

Hydrostatic flared disk, i = 84Dust + gas suspended above midplaneConsistent with T(r), (r) for irradiated disks (D’Alessio et al. 1999)

Multiwavelength Models

ISM Dust: Opacity decreases by 10 from V to KDust lane width decreases into IRVery compact nebulosity at K

Wood et al. 1998

V (0.55m) I (0.85m) K (2.25m)

Cotera et al. 2001

V (0.55m) I (0.85m) K (2.25m)

NICMOS: Wide dust lane at K

Circumstellar dust is GRAYER than ISM dust

Grain Growth in disk

HH 30 IRS: SED Models

Model:Geometry from HST images;Heating: starlight + accretion

Model HST images and SED: Determine dust size distributionFind: Grayer opacity

Optical opacity < ISMLarger disk mass (~ M)Md ~ 2 * 10-3 M

Wood et al. 2002

HH 30 IRS: Grain Growth

ISMHH 30 IRS

m506.05.3

/exp~)(

c

qc

p

aqp

aaaan

Dust Size Distribution:Power law + exponential decayGrain Sizes in excess of 50mGrayer opacity, Sub-mm slope ~ 1/

Beckwith & Sargent (1991): sub-mm continuum SEDs: ~ 1/

HH 30 IRS: Image Variability

Magnetic Accretion in HH 30 IRS• Stellar BB-field not aligned with rotation axis

• Truncates disk, accretion along field lines

• Hot Spots on star at magnetic poles

• UV excess, photometric modulation

BB

Ghosh & Lamb1979Shu et al. 1994

Magnetic Accretion in HH 30 IRS

Wood & Whitney 1998

Magnetic Accretion in HH 30 IRS• T*=3500K; Ts=10000K; A ~ 6%

• Asymmetric brightening; V ~ 1.5m

• Photometric centroid shift: ~ 0.5’’

Wood & Whitney 1998

Stapelfeldt et al. 1999

HH 30 IRS: Photometry

V ~ 1.5mag, T ~ days: Typical of CTTs, accretion hot spotsVariability all due to scattered light

Wood et al. 2000

GM Aur: Disk/Planet Interaction?

• NICMOS coronagraph

• Scattered light modeling:

• Mdisk ~ 0.04 M; Rdisk ~ 300 AU; i ~ 50

Schneider et al. 2002

1200 AU

GM Aur: Disk/Planet Interaction?

• No near-IR excess• SED model requires 4AU gap: planet?• Lin & Papaloizou; Seyer & Clarke; Nelson, etc

GM Aur: Disk/Planet Interaction?

• 3D SPH calculation from Ken Rice

• Planet at 2.5 AU clears disk out to 4AU

Rice et al. 2002

GM Aur: Disk/Planet Interaction?

• 3D SPH calculation from Ken Rice

• Planet at 2.5 AU clears disk out to 4AU

Rice et al. 2002

GM Aur: Disk/Planet Interaction?

• 3D SPH density grid into Monte Carlo code• SIRTF SED can discriminate planet mass• Centroid shifting ~ 0.1mas: Keck, SIM?

Rice et al. 2002

Disk Evolution

Lada et al. 2000

Trapezium ClusterIR-EXCESS = DISKSIR-EXCESS = DISKSCluster age ~ 1.5MyrDisk Frequency: 80%

Disk Lifetimes

Haisch et al. 2000

CLUSTER SURVEYS:CLUSTER SURVEYS:Disk frequency declines with cluster ageDisk Lifetime: ~ 6Myr

Disk Evolution

• Disk structure does not change

• Disk mass decreases homologously

• Mass = mass of dust contributing to SED

• What Md can near-IR surveys detect?

• Observables: SEDs, colors

• Current evidence for disk mass evolution?

SED Evolution

d = 500pc; 10-8 M < Md < 10-1 M

SIRTF 5, 500secs

Wood et al. 2002

Color Evolution

Wood et al. 2001

Observing Disk Evolution

• JHKL surveys: disk frequency & lifetime

• JHKL surveys: detect Md > 10-7M

• Far-IR & (sub)mm: disk mass evolution

• Mid-IR (10m & 25m): disk mass evolution

Taurus-Auriga Sources

Gap in K-N distribution: transition from disks to no disksKenyon & Hartmann 1995

* = I+ = II( = III

Disk Masses in Taurus-Auriga

Evolution models: disk clearing rapid for Md < 10-6 MWood et al. 2002

1 = 10-1 M

2 = 10-2 M

3 = 10-3 M

etc

Space Infrared Telescope

• SIRTF: launch in January 2003

• Lot’s of data: 6 Legacy programs

• Infrared spectra for 3m < < 160m

• Study disks: environments and ages

• Website with grid of models

Feedback in Star Formation

• HH 30 IRS, GM Aur: Signatures of magnetic accretion & SPH models

• Bigger Goal: Combine RT and hydro simulations

• Temperature, radiation pressure & ionization structure

Disk Temperature Structure

• Stellar photons absorbed at ~ 4 h(r) above midplane• Iterate with dynamics • Self-consistent disk structure

6 AU 20 AU 300 AU

T

1/5

Summary & Future Research

• Disk Structure & Variability: HH 30, GM Aur

• Model data with analytic density structures

• Now testing hydro simulations

• SIRTF: characterize large numbers of disks

• Goal: merge radiation transfer & hydro

Monte Carlo Photoionization

T* = 40000 KQ(H0) = 4.26 1049 s-1

n(H) = 100 cm-3

Calculate 3D ionization structure Study percolation of ionizing photons in fractal ISM

Stromgren Volume in a Dickey-Lockman Disk

2 Kpc

n(H0) Ionization fraction

f ~ 10-3

Q(H0) = 2 1050 s-1: Escape fraction = 22%Ionization of HVCs, Magellanic Stream, IGM…

3D Stromgren Volumes

n(H0) (before) Ionization fraction n(H0) (after)

Clumpy density; 2 sources with Q(H0) = 2 1050 s-1 3D ionization structure, shadow regions