A Submillimeter View of Protoplanetary Disks

1
A Submillimeter View of Protoplanetary Disks
Sean Andrews
University of Hawaii Institute for Astronomy
and
Jonathan Williams Rita Mann, UH IfA
David Wilner, Harvard-Smithsonian CfA
2
outline

• sub-mm photometry of Tau-Aur disks

- outer disk fraction and radial evolution
timescale - disk mass and sub-mm color evolution
3
constraints on the planet formation process
viscous accretion photoevaporation particle growth
?
initial conditions
final products
empirical constraints from sub-mm observations
4
Q why sub-mm observations? A to trace most
of the disk
SED thermal emission from irradiated thin dust
disk different disk regions contribute at
different l based on local temperature and
density conditions
5
Q why sub-mm observations? A to resolve the
disk structure
spatial emission distribution low sub-mm optical
depths continuum emission sensitive to
distribution of density near the disk midplane
1-2
0.3
angular resolution
0.5 km
100 m
baseline lengths
6
Multiwavelength Single-Dish Survey of Disks

• 153 Taurus disks 47 Ophiuchus disks (SpT lt M5,
  1-3 Myr)
• 350, 450, and 850 mm deep and uniform (3s to
  lt10 mJy)

SCUBA
SHARC-II
7
evolution of outer disk properties
sub-mm emission (disk masses) decreases with IR
SED evolution
sub-mm SED changes with IR SED
evolution (particle growth)
Andrews Williams (2005)
8
outer disk fraction/radial evolution timescales
9
SMA Imaging Survey of Protoplanetary Disks

• 24 disks with 1-2 resolution at 880 mm / 1.3
  mm
• continuum 12CO J3-2 / J2-1

Andrews Williams (2007)
10
1500 AU
12 disks in Tau-Aur and 12 in Oph-Sco
041582805 AA Tau CI Tau DH Tau
DL Tau DM Tau DN Tau DR Tau
FT Tau GM Aur GO Tau RY Tau
AS 205 AS 209 DoAr 25 DoAr 44
Elias 24 GSS 39 L1709 B SR 21
SR 24 WaOph 6 WSB 60 WL 20
10
measuring circumstellar disk structure
geometrically thin irradiated disk
simultaneously fit SED SMA visibilities
S ? R-p
Rd
T ? R-q
Md
SED
visibilities
11
measuring circumstellar disk structure
geometrically thin irradiated disk
simultaneously fit SED SMA visibilities
and repeat for 20 disks
derive temperature density distributions, disk
sizes
S ? R-p
Rd
T ? R-q
Md
1s
3s
5s
SED
visibilities
Dc2
12
disk structure results
temperatures
T ? R-q median q ? 0.6 1 AU temperature ? 200 K
densities
S ? R-p median p ? 0.7-1.0 1 AU surface density
? 150 g/cm2
sizes and masses
median Rd ? 200 AU median Md ? 0.05 solar masses
Andrews Williams (2007) see also, e.g., Lay et
al. (1997), Kitamura et al. (2002), etc.
13
comparison with viscous accretion disk properties
to conserve angular momentum, disk spreads thin
as it accretes
14
comparison with viscous accretion disk properties
n a cs H
sets timescale
change in S and Rd with age
a 0.01
Hartmann et al. (1998) fiducial model behavior
15
a different environment Taurus to Orion
16
a different environment Taurus to Orion
quiescent, low-mass
does enough disk mass remain to form planetary
systems?
crowded, high-mass
mass loss rate of 10-7 M?/yr evaporation
timescale of 105 yr
Churchwell et al. (1987)
photoevaporating proplyds
C. R. ODell
17
detecting thermal disk emission in the Trapezium
18
detecting thermal disk emission in the Trapezium
BIMA
OVRO
PdBI

• high spatial resolution
• filter out cloud emission
• separate disks in crowded region

• high frequency
• more sensitive to thermal emission
• less contamination

Mundy et al. (1995)
Bally et al. (1998)
Lada (1999)
Williams, Andrews, Wilner (2005)
l 1 cm
1 mm
19
masses of the Orion proplyds
0.019 M?
0.016 M?
0.024 M?
0.013 M?
Williams, Andrews, Wilner (2005)
4/23 disks with Md ? MMMSN
see also Eisner Carpenter (2006)
20
masses of the Orion proplyds
detection statistics (10-20)?
21
summary