Massive Star Massive Star Formation:Formation:

The Role of DisksThe Role of DisksCassandra Cassandra FallscheerFallscheer

In collaboration with:In collaboration with:

Henrik Beuther, Eric Keto, JHenrik Beuther, Eric Keto, Jürgen Sauter, ürgen Sauter, TK Sridharan, Sebastian Wolf, Qizhou ZhangTK Sridharan, Sebastian Wolf, Qizhou Zhang

Great Barriers in Massive Star Great Barriers in Massive Star Formation September 16, 2010Formation September 16, 2010

Three sources in an evolutionary Three sources in an evolutionary sequencesequence

• Infrared ObservationsInfrared Observations

• CC1818O line widthO line width

• Decrease in size of possible disk Decrease in size of possible disk observationsobservations

Am

plit

ud

e (

Jy/b

eam

)

IRDC 18223-3 IRAS 18151-1208 IRAS 18507+0121

Three Case StudiesThree Case Studies

•IRDC 18223-3IRDC 18223-3

•IRAS 18151-1208IRAS 18151-1208

•IRAS 18507+0121IRAS 18507+0121

AGE

IRDC 18223-3: Infrared Dark IRDC 18223-3: Infrared Dark CloudCloud

• Distance~3.7 kpcDistance~3.7 kpc

Beuther, Sridharan & Saito 2005

3-color Spitzer image with 3mm cont. contours

1.2 mm single dish contours,

8 micron MSX image

1 pc

IRDC 18223-3: Infrared Dark IRDC 18223-3: Infrared Dark CloudCloud

• Distance~3.7 kpcDistance~3.7 kpc

Beuther, Sridharan & Saito 2005

3-color Spitzer image with 3mm cont. contours

1.2 mm single dish contours,

8 micron MSX image

1 pc

Rolf Kuiper’s talk tomorrow

Fallscheer et al. 2009, A&A, 504, 127

outfl

ow

CH3OH Velocity Moment Map

Infall modelInfall model

Density distribution Velocity distribution

Input quantities:

50 Msun

1.5 km/s observed at 14000 AU

Model collapse of an initially rotating structure

Model includes gravity and conserves angular momentum

104 AU

Three Case StudiesThree Case Studies

•IRDC 18223-3IRDC 18223-3

•IRAS 18151-1208IRAS 18151-1208

•IRAS 18507+0121IRAS 18507+0121

AGE

The high mass protostellar The high mass protostellar object IRAS 18151-1208object IRAS 18151-1208• 3.0 kpc away3.0 kpc away

Davis et al. 2004, A&A, 425, 981

3000 AU

Modeling Modeling with MC3Dwith MC3D

Low Mass:Low Mass:Butterfly Butterfly StarStar

High mass: High mass: IRAS 18151-IRAS 18151-12081208

αα, radial , radial density density parameterparameter

2.42.4 2.42.4

ββ, disk flaring , disk flaring parameterparameter

1.31.3 1.31.3

MMdustdust 0.0007 M0.0007 M 2.2 M2.2 M

RRoutout, radius , radius where where density=0density=0

300 AU300 AU 5000 AU5000 AU

RR**, T, T**, L, L** 2 R2 R, 4000 K, , 4000 K, 0.92 L0.92 L

6.4 R6.4 R, 25400 , 25400 K, 16000 LK, 16000 L

Observations+/- 1σModel

____

………

- - - -

Fallscheer et al. 2010, submitted

Predictions for the FuturePredictions for the Future

•Predictions for ALMA, JWST, E-ELTPredictions for ALMA, JWST, E-ELT•Mid-infrared to millimeter Mid-infrared to millimeter

wavelengthswavelengths

Three Case StudiesThree Case Studies

•IRDC 18223-3IRDC 18223-3

•IRAS 18151-1208IRAS 18151-1208

•IRAS 18507+0121IRAS 18507+0121

AGE

Hot Molecular Core: IRAS Hot Molecular Core: IRAS 18507+012118507+0121

• LLbolbol~32,000 L~32,000 Lsun sun (O9.5)(O9.5)

• D~3.9 kpcD~3.9 kpc

• Moment maps do not Moment maps do not reveal evidence for reveal evidence for rotationrotation

Points to rememberPoints to remember

• Three sources in an evolutionary sequence Three sources in an evolutionary sequence may be used to deduce a scenario for disk may be used to deduce a scenario for disk evolutionevolution

• Elongated disk-like features decrease with Elongated disk-like features decrease with evolutionary stageevolutionary stage

• 20,000 AU velocity structure can be 20,000 AU velocity structure can be reproduced with a collapsing rotating reproduced with a collapsing rotating model…disk possibly in the centermodel…disk possibly in the center

• Elongation in the dust continuum modelled Elongation in the dust continuum modelled with a scaled up version of a low mass diskwith a scaled up version of a low mass disk

How the parameters affect the How the parameters affect the SEDSED

H0 =5H0=10H0=15

θ=60° θ=90°

M=2.2M=1.2

Scale height at 100AU

Inclination Angle

Central star Dust mass of disk

The importance of short The importance of short spacingsspacings

• Comparison with and without short spacingsComparison with and without short spacings

+ =

Where new files come fromWhere new files come from

• SED & Radial Brightness profile: run 68SED & Radial Brightness profile: run 68

• SED H_0: seds 61, 59B, 53SED H_0: seds 61, 59B, 53

• SED theta: 67A,67BSED theta: 67A,67B

• SED mass: 68,67ASED mass: 68,67A

• Img68.jpgImg68.jpg

• JWST/E-ELT Figure from Henrik, JWST/E-ELT Figure from Henrik, overlay_cassie.epsoverlay_cassie.eps