WATER VAPOR IN THE PROTOPLANETARY DISK OF DG Tau

Journal Article · Wed Mar 20 00:00:00 EDT 2013 · Astrophysical Journal Letters

DOI:https://doi.org/10.1088/2041-8205/766/1/L5· OSTI ID:22130812

Podio, L.; Dougados, C.; Thi, W. -F.; Menard, F.; Pinte, C. ^[1]; Kamp, I.; Meijerink, R.; Spaans, M.; Aresu, G. ^[2]; Codella, C. ^[3]; Cabrit, S. ^[4]; Nisini, B. ^[5]; Sandell, G. ^[6]; Williams, J. P. ^[7]; Testi, L. ^[8]; Woitke, P. ^[9]

---

1. UJF-Grenoble 1/CNRS-INSU, Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) UMR 5274, F-38041 Grenoble (France)
2. Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen (Netherlands)
3. INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125 Florence (Italy)
4. LERMA, UMR 8112 du CNRS, Observatoire de Paris, Ecole Normale Superieure, Universite Pierre et Marie Curie, Universite de Cergy-Pontoise, 61 Av. de l'Observatoire, F-75014 Paris (France)
5. INAF-Osservatorio Astronomico di Roma, via di Frascati 33, I-00040 Monte Porzio Catone (Italy)
6. SOFIA-USRA, NASA Ames Research Center, MS 232-12, Building N232, Rm. 146, P.O. Box 1, Moffett Field, CA 94035-0001 (United States)
7. Institute for Astronomy (IfA), University of Hawaii, 2680 Woodlawn Dr., Honolulu, HI 96822 (United States)
8. European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching (Germany)
9. SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS (United Kingdom)

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 water ice reservoirs are stored, was only reported in the nearby 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 and 1113 GHz. The lines show a narrow double-peaked profile, consistent with an origin in the outer disk, and are {approx}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 H{sub 2}O 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 M{sub Sun }, consistent with the estimated minimum mass of the solar nebula before planet formation, and a water reservoir of {approx}10{sup 2}-10{sup 3} Earth oceans in vapor and {approx}100 times larger in the form of ice. Hence, this detection supports the scenario of ocean delivery on terrestrial planets by the impact of icy bodies forming in the outer disk.

• OSTI ID: 22130812
• Journal Information: Astrophysical Journal Letters, Vol. 766, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
CARBON MONOXIDE
DELIVERY
DETECTION
EMISSION
EVOLUTION
EXCITATION
GROUND STATES
ICE
IRRADIATION
LAYERS
MASS
MOLECULES
PROTOPLANETS
SIMULATION
SOLAR NEBULA
T TAURI STARS
TELESCOPES
WATER
WATER VAPOR