Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk

E. A. Bergin (1) , M. R. Hogerheijde , C. Brinch , J. Fogel , U. A. Yildiz , L. E. Kristensen , E. F. Van~dishoeck , T. A. Bell , G. A. Blake (2) , J. Cernicharo (3) , C. Dominik (4) , D. Lis (5) , G. Melnick (5) , D. Neufeld (5) , O. Panic , J. C. Pearson , R. Bachiller (5) , Alain Baudry (6, 7, 8, 9) , M. Benedettini (5) , A. O. Benz , P. Bjerkeli , Sylvain Bontemps (6, 7, 8, 9) , J. Braine (6, 7, 8, 9) , S. Bruderer , P. Caselli (10) , C. Codella (5) , F. Daniel , A. M. Di Giorgio , S. D. Doty , P. Encrenaz (11) , M. Fich , A. Fuente (5) , T. Giannini , J. R. Goicoechea (11) , Th. de Graauw , F. Helmich (5) , G. J. Herczeg , Fabrice Herpin (6, 7, 8, 9) , T. Jacq (6, 7, 8, 9) , D. Johnstone , J. K. Jorgensen , B. Larsson (5) , R. Liseau , M. Marseille (6, 7, 8, 9, 12) , C. Mccoey , B. Nisini (13) , M. Olberg (14) , B. Parise (15) , R. Plume , C. Risacher (16) , J. Santiago-Garcia , P. Saraceno (17) , R. Shipman , M. Tafalla , T. A. van Kempen , R. Visser , S. F. Wampfler , F. Wyrowski (18) , F. van Der Tak (5) , W. Jellema , A. G. G. M. Tielens (12) , P. Hartogh (19) , J. Stutzki (5) , R. Szczerba

1 CfA - Harvard-Smithsonian Center for Astrophysics
2 LOCIE - LabOratoire proCédés énergIe bâtimEnt
3 CSIC - Centro de Investigaciones Biológicas
4 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
5 LAOG - Laboratoire d'Astrophysique de Grenoble
6 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
7 OASU - Observatoire aquitain des sciences de l'univers
8 UB - Université Sciences et Technologies - Bordeaux 1
9 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
10 OAA - INAF - Osservatorio Astrofisico di Arcetri
11 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
12 SRON - SRON Netherlands Institute for Space Research
13 OAR - INAF - Osservatorio Astronomico di Roma
14 Onsala Space Observatory
15 CESR - Centre d'étude spatiale des rayonnements
16 ESO
17 IFSI - Istituto di Fisica dello Spazio Interplanetario
18 MPIFR - Max-Planck-Institut für Radioastronomie
19 MPS - Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research

We performed a sensitive search for the ground-state emission lines of ortho- and para-water vapor in the DM Tau protoplanetary disk using the Herschel/HIFI instrument. No strong lines are detected down to 3sigma levels in 0.5 km/s channels of 4.2 mK for the 1_{10}--1_{01} line and 12.6 mK for the 1_{11}--0_{00} line. We report a very tentative detection, however, of the 1_{10}--1_{01} line in the Wide Band Spectrometer, with a strength of T_{mb}=2.7 mK, a width of 5.6 km/s and an integrated intensity of 16.0 mK km/s. The latter constitutes a 6sigma detection. Regardless of the reality of this tentative detection, model calculations indicate that our sensitive limits on the line strengths preclude efficient desorption of water in the UV illuminated regions of the disk. We hypothesize that more than 95-99% of the water ice is locked up in coagulated grains that have settled to the midplane.

Mots clés: Solar and Stellar Astrophysics; Astrophysics; Earth and Planetary Astrophysics

Domaines: Astrophysique stellaire et solaire [astro-ph.SR]; Astrophysique stellaire et solaire [astro-ph.SR]; Planétologie et astrophysique de la terre [astro-ph.EP]; Planétologie et astrophysique de la terre [astro-ph.EP]

E. A. Bergin, M. R. Hogerheijde, C. Brinch, J. Fogel, U. A. Yildiz, et al.. Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk. Astronomy and Astrophysics - A&A, 2010, 521, pp.id.L33. ⟨10.1051/0004-6361/201015104⟩. ⟨hal-00521381⟩