surface density structure in outer region of p rotoplanetary disk
DESCRIPTION
Surface Density Structure in Outer Region of P rotoplanetary Disk. Jul. 24th 2014 Nobeyama UM Eiji Akiyama (NAOJ) Munetake Momose , Yoshimi Kitamura, Takashi Tsukagosh , Shota Shimada, Masahiko Hayashi, Shin Koyamatsu. Importance of Outer Region of the Disk. How is disk gas cleared ? - PowerPoint PPT PresentationTRANSCRIPT
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Surface Density Structure in Outer Region of Protoplanetary Disk
Jul. 24th 2014 Nobeyama UMEiji Akiyama (NAOJ)
Munetake Momose, Yoshimi Kitamura, Takashi Tsukagosh, Shota Shimada, Masahiko Hayashi, Shin Koyamatsu
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Importance of Outer Region of the Disk• How is disk gas cleared ?• How can planets form at a distant from a central star ?
Kalas et al. 2009
Fomalhaut
r = 119 AU
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Power Law Disk Model
Power law description in surface density was introduced in the minimum mass solar nebula. (e.g. Kusaka et al. 1970, Weidenschilling 1977, Hayashi et al. 1985)
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Discrepancy between Dust & Gas EmissionDiscrepancy in disk size has emerged between the extent of the dust continuum and molecular gas emission. Dust continuum: smaller size Gas emission: larger sizeExamples・ AB Aur (Pietu et al. 2005)
Continuum (2.8, 1.4mm) : 350±30 AU12CO(J=2-1) :
1050±10 AU
・ HD 163296 (Isella et al. 2007)Continuum (0.87-7mm) : 200±15 AU12CO(J=3-2) etc : 540±40 AU
Is the power law description really appropriate ?
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Similarity Solution Disk Model Surface density is based on the theory of viscous evolution
(Lynden-Bell & Pringle 1974, Hartmann et al. 1998)
Radial temperature distribution Same as power-law disk model
power-law
similarity
x[AU]
y[A
U]
y[A
U]
x[AU]
log nH2
[1/cc]
Log r [AU]
Log
Σ(r
) [g
cm
-2]
rout
power-law
similarity
distance where Σ(r) starts decreasing exponentially
normalized surface density
C2
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Examples of Similarity Solution
velocity [km s-1]
HD163296
R.A.
Dec
.
2 4 6 8 2 4 6 8 2 4 6 8
PowerSimilarity
Hughes et al. 2008
ALMA SVband7
color: CO(3-2)contour: continuum
10 100 1000r [AU]
CO(3-2)continuum
rc = 125 AU
de Gregorio-Monsalvo et al. 2013
10-2
10-3
10-4
10-1
10-1
10-2
10-3
10-0
CO
(3-2) [Jy/beam]
cont
inuu
m [
Jy/b
eam
]
10
8
6
4
2
Vel. [km
/s]
CO(3-2)
2
0
4
6
24
6
offs
et [
arcs
ec]
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Gallery of Protoplanetary Disks (Radio)
Andrews et al. 2011 Mathew et al. 2012Brown et al. 2012 Cieza et al. 2012Isella et al. 2010
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Object Details
distance [pc] SP type M* [M☉] Mdisk [M☉] inclination [deg.]
140 A2/3 2.3 0.029 38
• MWC 480 is bright Herbig Ae star with primordial disk.• Many people have observed and basic properties are well known.• No complex structures → easy to analyze the structure
Kusakabe et al. 2012 Acke & van den Ancker 2004
No complex structures
log λ[μm]
log
λFλ
[erg
cm
-2s-1
μm
]H-band
Subaru
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Observation Details
TelescopeReciever
NRO45, ASTEBEARS, T100H/V, CATS345
Lines 12CO(1-0), 13CO(1-0), C18O(1-0), 12CO(3-2), 13CO(3-2)
Frequency 109 – 115 GHz, 330 – 345 GHz
Spatial res. ~ 15” (~2100 AU), ~ 23”(~3200 AU)
Velocity res. ~ 0.055 – 0.1 km/s
Integ. time 4.2h (2.0h on source)
System temp. 140 -350 K
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Model Parameters・ Fixed parameters : The results obtained by other observations applied
・ Free parameters : Best fit parameters are searched
・ X ( 12CO) = 10000 ・ Local Thermal Equilibrium (LTE)
・ X ( 12CO) / X ( 13CO) = 60 ・ Hydrostatic Equilibrium
・ X ( 13CO) / X ( C18O) = 5
・ Outer radius : rout (C2)・ Temperature : T100 ・ Surface density : Σ100
(C1)
distance [pc]
M* [M☉]
inclination [deg.]
p q
HD163296 140 2.3 38 1.0 0.5
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Model Fit Results
Similarity solution shows better fit in multi-CO line observation → It supports viscous evolution
Akiyama et al. 2013
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Observation Details
Lines 12CO(2-1), 13CO(2-1), C18O(2-1)
Frequency 219 – 230 GHz
Spatial res. ~ 0.68” x ~ 0.55”
FoV ~ 27”
Proj. baseline 16 – 400 m
Velocity res. 0.3 – 0.66 km/s
Integ. time 4.2h (2.0h on source)
System temp. 60 -180 K (0.8mm water vapor)
ALMA SV band 6
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Results (ALMA SV band 6)
12CO(2-1)
13CO(2-1)
C18O(2-1)
0th 1st 2nd
Akiyama et al. submitted
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Results (ALMA SV band 6)
12CO(2-1)
13CO(2-1)
C18O(2-1)
0th 1st 2nd
Akiyama et al. submitted
Vlsr [km s-1]
Flu
x D
ensi
ty [
Jy]
12CO(2-1) 13CO(2-1) C18O(2-1)
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Successful Example of SS Model 1
Akiyama et al.
submitted
CO (2-1) 13CO (2-1) C18O (2-1)
PL
SS
700
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Successful Example of SS Model 2rout = 700AU, p=1.0, θ=45°
T100 [K]
Σ100 [gm s-1] 12CO(J =3-2) 13CO(J =3-2) 12CO(J =1-0) 13CO(J =1-0)
0.001
12CO(J =3-2) 13CO(J =1-0) 13CO(J =3-2)4030
20
100
0
0.15
0.312CO(J =1-0)
1.5
3
0
-100
10
20
30
Tm
b [K
]
3
1.5
0
-1.5
Tm
b [K
]
40
-0.15
0
0.15
0.3
201510
50
-5201510
50
-5-10
0 2 4 6 8 10 12 Vlsr [km s-1]
0 2 4 6 8 10 12 Vlsr [km s-1]
0 2 4 6 8 10 12 Vlsr [km s-1]
0 2 4 6 8 10 12 Vlsr [km s-1]
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Summary
1. MWC 480 was selected for its simple disk structure.
2. Similarity solution model is based on the viscous evolution. → Surface density tapers off gradually with distance.
3. Similarity solution reproduces the observation ・ Verified by NRO45/ASTE (single dish) and ALMA SV (interferometry) and data. ・ Similarity solution model is more suitable than power law for describing disks. → The disk evolves via viscous diffusion