Clustered Star Formation

1
Clustered Star Formation
- Cluster forming clumps in the Rosette
- Internal (collapse?) motions in W3
- The masses of the Orion proplyds
Jonathan Williams Institute for Astronomy (UH
Manoa)
2
Massive stars form in clusters in Giant Molecular
Clouds
Y. Fukui
3
Heyer, Williams Brunt in prep
4
with Meredith Hughes (REU)
5
(No Transcript)
6
LIRAS / MCLUMP
Heyer, Williams Brunt in prep
7
(No Transcript)
8
Young stellar clusters in the RMC
M tens of Mc, R 0.3 pc, Dv few km/s
No clear trends of NIR properties with L/M, HII
distance, morphology, etc!
L/M24
46
lt 1
bound, n(H2) 103-4 cm-3, S 0.02 g/cm2
2
125
114
Carlos Roman PhD
9
Chemistry of cluster envelopes
Dust
10
Velocity gradients
Low density tracers have small or non-existent
gradients incoherent/turbulent motion Higher
density tracers have much more ordered motions
with high velocity gradients transition to
coherence? (c.f. Goodman et al. 1998)
11
Internal (collapse?) motions in W3
W3(H2O)
W3(OH) compact HII region O7 star
Turner-Welch object
M 15 Mc L 3x104 Lc 2 proto-B-stars?
Wyrowski et al. 1999
12
W3 SMA 1.3mm continuum
OH
H2O
6 0.07pc
preliminary results with Sandrine Bottinelli
13
CO(2-1) absorption of both continuum sources
14
A toy model
rear emitting layer
H2O
OH
stationary absorbing layer
15
Two-layer radiative transfer model
N
16
A toy model
rear emitting layer
0.8 km/s
0.5 km/s
2 km/s
H2O
OH
0.5 km/s
stationary absorbing layer
17
Differentially rotating clump?
18
Interferometric absorption studies
- a reliable way to map relative motions - more
feasible at high frequencies (SMA!) higher
line optical depth, greater continuum strength
Welch et al. (1987)
19
The masses of the Orion proplyds
20
The masses of the Orion proplyds
Tightly clustered objects Background cloud
emission Strong bremsstrahlung emission
21
The masses of the Orion proplyds
Tightly clustered objects Background cloud
emission Strong bremsstrahlung emission
22
(Bally et al. 1998)
23
0.019 Mc
4/23 proplyds have enough material to form Solar
System scale planetary systems
0.013 Mc
0.023 Mc
0.017 Mc
24
What about the non-detections? (18 are lt 3s)
(Williams, Andrews, Wilner 2005)
25
3 7s, 1 3s detection but 18 non-detections
sudden mass loss event?
are the proplyds on circular or radial
orbits? (Storzer Hollenbach)
26
5 detections, 4 dust masses
M gt minimum mass solar nebula enough
material to form Solar System architectures
27
18 non-detections
positive average flux M 2x10-4
Msun uneven mass distribution rapid mass
loss event?
radial orbits? (Storzer Hollenbach 2003)
28
High mass stars affect many more planetary
systems if stars move on radial (rather than
circular) orbits
Future observations proplyd mass
distribution and distance dependence
29
(No Transcript)
30
(No Transcript)
31
(No Transcript)