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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 ?
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Surface Density Structure in Outer Region of Protoplanetary Disk Jul. 24th 2014 Nobeyama UMEiji Akiyama (NAOJ)MunetakeMomose, Yoshimi Kitamura, Takashi Tsukagosh,Shota Shimada, Masahiko Hayashi, Shin Koyamatsu
Importance of Outer Region of the Disk • How is disk gas cleared ? • How can planets form at a distant from a central star ? Fomalhaut r = 119 AU Kalas et al. 2009
Power Law Disk Model • Power law description in surface densitywasintroduced in the minimum mass solarnebula. (e.g. Kusaka et al. 1970, Weidenschilling 1977, Hayashi et al. 1985)
Discrepancy between Dust & Gas Emission Discrepancy in disk size has emerged between the extent of the dust continuum and molecular gas emission. Dust continuum: smaller size Gas emission: larger size Examples・AB Aur (Pietu et al. 2005) Continuum (2.8, 1.4mm) : 350±30AU12CO(J=2-1) : 1050±10AU ・HD 163296 (Isella et al. 2007) Continuum (0.87-7mm) : 200±15AU12CO(J=3-2) etc : 540±40AUIs the power lawdescriptionreallyappropriate ?
Similarity Solution Disk Model power-law • Surface densityis based on the theory of viscousevolution (Lynden-Bell & Pringle 1974, Hartmann et al. 1998) • Radial temperature distributionSame as power-law disk model y[AU] normalized surface density distance where Σ(r) starts decreasing exponentially log nH2[1/cc] x[AU] power-law similarity Log Σ(r) [g cm-2] similarity y[AU] rout C2 Logr [AU] x[AU]
Examples of Similarity Solution HD163296 10 ALMA SVband7 color: CO(3-2)contour: continuum 8 6 Power Similarity CO(3-2) Vel. [km/s] 4 6 Dec. 2 4 offset [arcsec] 0 2 2 4 R.A. 6 CO(3-2) 10-1 10-0 continuum 2 4 6 8 2 4 6 8 2 4 6 8 velocity [km s-1] 10-2 10-1 CO(3-2) [Jy/beam] continuum [Jy/beam] 10-3 Hughes et al. 2008 10-2 rc = 125 AU 10-4 10-3 10 100 1000r [AU] de Gregorio-Monsalvo et al. 2013
Gallery of ProtoplanetaryDisks (Radio) Andrews et al. 2011 Mathew et al. 2012 Brown et al. 2012 Cieza et al. 2012 Isella et al. 2010
Object Details • MWC 480 is brightHerbigAe star with primordial disk. • Many people have observed and basic properties are well known. • No complex structures → easy to analyze the structure H-band log λFλ[erg cm-2s-1μm] Subaru log λ[μm] Acke & van den Ancker 2004 Kusakabe et al. 2012 No complex structures
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)
Model Fit Results Akiyama et al. 2013 Similarity solutionshows better fit in multi-CO line observation → It supports viscous evolution
Observation Details ALMA SV band 6
Results (ALMA SV band 6) 0th 1st 2nd 12CO(2-1) 13CO(2-1) C18O(2-1) Akiyama et al. submitted
Results (ALMA SV band 6) 0th 1st 2nd 12CO(2-1) 12CO(2-1) 13CO(2-1) C18O(2-1) 13CO(2-1) Flux Density [Jy] Vlsr [km s-1] C18O(2-1) Akiyama et al. submitted
Successful Example of SS Model 1 CO (2-1) 13CO (2-1) C18O (2-1) PL SS Akiyama et al. submitted 700
Successful Example of SS Model 2 rout = 700AU, p=1.0, θ=45° 12CO(J =1-0) 12CO(J =3-2) 13CO(J =1-0) 13CO(J =3-2) 20 40 0.3 3 15 30 0.15 10 1.5 20 5 Tmb [K] 10 0 0 0 0 -5 20 3 40 0.3 15 30 0.15 10 1.5 20 5 Tmb [K] 10 0 0 0 0 -5 -0.15 -1.5 -10 -10 0 2 4 6 8 10 12Vlsr [km s-1] 0 2 4 6 8 10 12Vlsr [km s-1] 0 2 4 6 8 10 12Vlsr [km s-1] 0 2 4 6 8 10 12Vlsr [km s-1]
Summary MWC 480 was selected for its simple disk structure. Similarity solution model is based on the viscous evolution.→ Surface density tapers off gradually with distance. 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