Evolved Protoplanetary Disks:

The Multiwavelength Picture

Aurora Sicilia-Aguilar

Th. Henning, J. Bouwman, A. Juhász, V. Roccatagliata,

C. Dullemond, L. Hartmann, D. WatsonMax-Planck-Institut für Astronomie

Tübingen, March 2 2009Tr 37, MIPS

24m

Multiwavelength data: a journey through Tr 37

Optical: 660 nm, T~5000 KNear-IR: T~600 K

3.6, 5.8, 8.0 m

IRAC

Mid-IR:

T~150 K

24 m MIPS

CO(1-0), T~20 K

2.6mm FCRAO

Sicilia-Aguilar et al. 2004 AJ 128, 805

Sicilia-Aguilar et al. 2006, ApJ 638, 897

Sicilia-Aguilar et al. 2006, ApJ 638, 897

Patel et al. 1998, ApJ 507, 241

Multiwavelength view of a protoplanetary disk

Geometrically thin, optically thick disk

Inner gaseous disk Optically thin

disk atmosphere

IR excess

UV excess

H emission10-8 Msun/yr ~ 10 MJ/ Myr

Flu

x

Flu

x

Log(/m)

V (km/s)

/m

Flu

x (

Jy)

Silicate feature

Pre-MS Star

~1-10 Myr

~0.1-3 Msun

H2

Chromospheric accretion

Solar-type star

~100-300 AU (0.7-2” in Taurus)

~0.01 Msun

Observing disk evolution with time

~ 1

0 M

yr

~

1 M

yr

V(km/s) log(/ m)

H

H

H

V(km/s) log(/ m)

V(km/s) log(/ m)

Typical CTTS

Flattened, accreting disk

Non-accreting TO Sicilia-Aguilar et al. 2006, AJ 132, 2135; SA+ in prep

?

But: All these objects have the same age!

The trend: Parallel dust and accretion evolution

Sicilia-Aguilar et al. 2006, ApJ 638, 897

Sicilia-Aguilar et al. 2006, AJ 132, 2135

Sicilia-Aguilar et al. in prep.

• IR excesses disappear, accretion decreases

• Same age, same mass, disk/no disk: Initial conditions? Binaries? (Bouwman et al. 2006, ApJ 653, 57)

Solar type stars

Non-accreting

“transition” objects

Transition objects (TO): On the way to planets?

Accreting TO: grain coagulation/planet formation.

Despite the age difference (1-2 vs. 4 Myr), they have the same dM/dt in Taurus and in Tr 37 , ~10-9 MA/yr (Najita et al. 2008; SA in prep.).

Non-accreting TO: grain coagulation/planet formation… or photoevaporation?

TW Hya: accreting TO with a planetSetiawan et al. 2008 (Nature 451, 38)

Other ways of producing inner holes: Binaries (e.g. CoKu Tau/4; Ireland & Kraus 2008)

Time evolution and stellar mass: “Transition” disks?

• Disk morphology/SEDs are different for M stars and solar-type stars.

• Flattened disks/”TO” seem more common for M-type stars.

• Are those “TO”/”evolved” disks really “in transition”?

Sicilia-Aguilar et al. 2008, ApJ,687, 1145

M0-M8 objects

Taurus, IC 348, 25 Ori data from Kenyon & Hartmann 1995; Hartmann et al. 2005; Briceño et al. 1998, 2007; Luhman et al. 2003; Hernández et al. 2007

Solar-type objects

Witnessing dust settling?

3 Myr-old K4.5 star:

average grain size 3 m

9 Myr-old K4.5 star:

average grain size 0.1 m

Sicilia-Aguilar et al. 2007

ApJ 659, 1637

• Grain growth/crystallization happens very early in the disk lifetime.

•Appropriate disk models are required (Bouwman et al. 2008; Juhász et al. 2009 )

What do the SED/silicate tell?

There is a general trend of IR excess & accretion evolution, but…

• Grain processing (growth to ~m, crystallization) must happen very early (<1 Myr).

• Multiple parameters play a role: binaries, disk/star mass, turbulence, environment

• Large individual variations: the key to understand disk evolution?

log(/ m) log(/ m)

log(

F /

erg

cm

-2 s

-1)

Which cluster is older ?

8 Myr 1 Myr

Summary and future

• Multiwavelength studies of clusters are required to trace the timescales and processes in disk dissipation.

• Accretion and IR excesses evolve in parallel, but…

• … individual objects are VERY different: key to disk dispersal?

• Mass, binarity, environment, and initial conditions may affect disk evolution.

Future: Herschel, JWST, ALMA,…