Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 2S028
WATER VAPOR IN THE PROTOPLANETARY DISK OF DG TAU
Podio, Linda (UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F- 38041, France)
Kamp, Inga (Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands)
Codella, Claudio (INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Florence, Italy)
Cabrit, Sylvie (LERMA, UMR 8112 du CNRS, Observatoire de Paris, École Normale Supérieure, Université Pierre et Marie Curie, Université de Cergy-Pontoise, 61 Av. de l’Observatoire, 75014, Paris, France)
Nisini, Brunella (INAF - Osservatorio Astronomico di Roma, via di Frascati 33, 00040, Monte Porzio Catone, Italy)
Dougados, Catherine (LFCA , UMI 3386, CNRS and Dept. de Astronomia, Universidad de Chile, Santiago, Chile --- UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F- 38041, France)
Sandell, Goran (SOFIA-USRA, NASA Ames Research Center, MS 232-12, Building N232, Rm. 146, P. O. Box 1, Moffett Field, CA 94035- 0001, U. S. A.)
Williams, Jonathan P. (Institute for Astronomy (IfA), University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI, 96822, USA)
Testi, Leonardo (European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany)
Thi, Wing-Fai (UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F- 38041, France)
Woitke, Peter (SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS, UK)
Meijerink, Rowin (Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands)
Spaans, Marco (Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands)
Aresu, Giambattista (Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands)
Ménard, Francois (LFCA , UMI 3386, CNRS and Dept. de Astronomia, Universidad de Chile, Santiago, Chile --- UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F- 38041, France)
Pinte, Christophe (UJF-Grenoble 1 / CNRS-INSU, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble, F- 38041, France)
Abstract:
Water is key in the evolution of protoplanetary disks and the formation of comets and icy/water planets. While high excitation water lines originating in the hot inner disk have been detected in several T Tauri stars (TTSs), water vapor from the outer disk, where most of water ice reservoir is stored, was only reported in the closeby TTS TW Hya. We present spectrally resolved Herschel/HIFI observations of the young TTS DG Tau in the ortho- and para- water ground-state transitions at 557, 1113 GHz. The lines show a narrow double-peaked profile, consistent with an origin in the outer disk, and are ~19−26 times brighter than in TW Hya. In contrast, CO and [C II] lines are dominated by emission from the envelope/outflow, which makes H2O lines a unique tracer of the disk of DG Tau. Disk modeling with the thermo-chemical code ProDiMo indicates that the strong UV field, due to the young age and strong accretion of DG Tau, irradiates a disk upper layer at 10–90 AU from the star, heating it up to temperatures of 600 K and producing the observed bright water lines. The models suggest a disk mass of 0.015–0.1 Msun, consistent with the estimated minimum mass of the solar nebula before planet formation, and a water reservoir of ~1e2−1e3 Earth oceans in vapour, and ~100 times larger in the form of ice. Hence, this detection supports the scenario of ocean delivery on terrestrial planets by impact of icy bodies forming in the outer disk.
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