Herschel -PACS observation of the 10 Myr old T Tauri disk TW Hya: Constraining the disk gas mass

W. F. Thi, G. Mathews, F. Ménard, P. Woitke, G. Meeus, P. Riviere-Marichalar, C. Pinte, C. D. Howard, A. Roberge, G. Sandell, I. Pascucci, B. Riaz, C. A. Grady, W. R.F. Dent, I. Kamp, G. Duchêne, J. C. Augereau, E. Pantin, B. Vandenbussche, I. TillingJ. P. Williams, C. Eiroa, D. Barrado, J. M. Alacid, S. Andrews, D. R. Ardila, G. Aresu, S. Brittain, D. R. Ciardi, W. Danchi, D. Fedele, I. De Gregorio-Monsalvo, A. Heras, N. Huelamo, A. Krivov, J. Lebreton, R. Liseau, C. Martin-Zaidi, I. Mendigutía, B. Montesinos, A. Mora, M. Morales-Calderon, H. Nomura, N. Phillips, L. Podio, D. R. Poelman, S. Ramsay, K. Rice, E. Solano, H. Walker, G. J. White, G. Wright

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Abstract

Planets are formed in disks around young stars. With an age of ∼10 Myr, TW Hya is one of the nearest T Tauri stars that is still surrounded by a relatively massive disk. In addition a large number of molecules has been found in the TW Hya disk, making TW Hya the perfect test case in a large survey of disks with Herschel-PACS to directly study their gaseous component. We aim to constrain the gas and dust mass of the circumstellar disk around TW Hya. We observed the fine-structure lines of [O i] and [C ii] as part of the open-time large program GASPS. We complement this with continuum data and ground-based 12 CO 3-2 and 13CO 3-2 observations. We simultaneously model the continuum and the line fluxes with the 3D Monte-Carlo code MCFOST and the thermo-chemical code ProDiMo to derive the gas and dust masses. We detect the [O i] line at 63 μm. The other lines that were observed, [O i] at 145 μm and [C ii] at 157 μm, are not detected. No extended emission has been found. Preliminary modeling of the photometric and line data assuming [ 12CO] /[13CO] = 69 suggests a dust mass for grains with radius <1 mm of ∼1.9 × 10-4 M⊙ (total solid mass of 3 × 10-3 M⊙) and a gas mass of (0.5-5) × 10 -3 M⊙. The gas-to-dust mass may be lower than the standard interstellar value of 100.

Original languageEnglish
Article numberL125
Number of pages6
JournalAstronomy and Astrophysics
Volume518
Issue number4
DOIs
Publication statusPublished - 15 Oct 2010
Externally publishedYes

Keywords

  • circumstellar disks

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