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dc.creatorFedele, Davideen_US
dc.creatorBruderer, Simonen_US
dc.creatorvan Dishoeck, Ewine F.en_US
dc.creatorCarr, J.en_US
dc.creatorHerczeg, G. J.en_US
dc.creatorSalyk, C.en_US
dc.creatorEvans, Neal J.en_US
dc.creatorBouwman, J.en_US
dc.creatorMeeus, Gwendolynen_US
dc.creatorHenning, Thomasen_US
dc.creatorGreen, Joelen_US
dc.creatorNajita, J. R.en_US
dc.creatorGudel, M.en_US
dc.date.accessioned2016-04-22T19:48:41Z
dc.date.available2016-04-22T19:48:41Z
dc.date.issued2013-11en
dc.identifierdoi:10.15781/T22V3F
dc.identifier.citationFedele, Davide, Simon Bruderer, Ewine F. Van Dishoeck, J. Carr, G. J. Herczeg, C. Salyk, N. J. Evans et al. >DIGIT survey of far-infrared lines from protoplanetary disks-I.[O i],[C ii], OH, H2O, and CH+.> Astronomy & Astrophysics, Vol. 559 (Nov., 2013): A77.en_US
dc.identifier.issn0004-6361en_US
dc.identifier.urihttp://hdl.handle.net/2152/34555
dc.description.abstractWe present far-infrared (50-200 mu m) spectroscopic observations of young pre-main-sequence stars taken with Herschel/PACS as part of the DIGIT key project. The sample includes 16 Herbig AeBe and 4 T Tauri sources observed in SED mode covering the entire spectral range. An additional 6 Herbig AeBe and 4 T Tauri systems have been observed in SED mode with a limited spectral coverage. Multiple atomic fine structure and molecular lines are detected at the source position: [OI], [CII], CO, OH, H2O, CH+. The most common feature is the [OI] 63 mu m line detected in almost all of the sources, followed by OH. In contrast with CO, OH is detected toward both Herbig AeBe groups (flared and non-flared sources). An isothermal LTE slab model fit to the OH lines indicates column densities of 10(13) < N-OH < 10(16) cm(-2), emitting radii 15 < r < 100 AU and excitation temperatures 100 < T-ex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n greater than or similar to 10(10) cm(-3)) are needed to reproduce the observations. The OH emission thus comes from a warm layer in the disk at intermediate stellar distances. Warm H2O emission is detected through multiple lines toward the T Tauri systems AS 205, DG Tau, S CrA and RNO 90 and three Herbig AeBe systems HD 104237, HD 142527, HD 163296 (through line stacking). Overall, Herbig AeBe sources have higher OH/H2O abundance ratios across the disk than do T Tauri disks, from near-to far-infrared wavelengths. Far-infrared CH+ emission is detected toward HD 100546 and HD 97048. The slab model suggests moderate excitation (T-ex similar to 100 K) and compact (r similar to 60 AU) emission in the case of HD 100546. Off-source [OI] emission is detected toward DG Tau, whose origin is likely the outflow associated with this source. The [CII] emission is spatially extended in all sources where the line is detected. This suggests that not all [CII] emission is associated with the disk and that there is a substantial contribution from diffuse material around the young stars. The flux ratios of the atomic fine structure lines ([OI] 63 mu m, [OI] 145 mu m, [CII]) are analyzed with PDR models and require high gas density (n greater than or similar to 10(5) cm(-3)) and high UV fluxes (G(o) similar to 10(3)-10(7)), consistent with a disk origin for the oxygen lines for most of the sources.en_US
dc.description.sponsorshipNASA by the Jet Propulsion Laboratory, California Institute of Technologyen_US
dc.description.sponsorshipNetherlands Research School for Astronomy (NOVA)en_US
dc.description.sponsorshipNetherlands Organisation for Scientific Research (NWO) 614.001.008en_US
dc.description.sponsorshipEuropean Community 238258, 291141en_US
dc.description.sponsorshipBMVIT (Austria)en_US
dc.description.sponsorshipESA-PRODEX (Belgium)en_US
dc.description.sponsorshipCEA/CNES (France)en_US
dc.description.sponsorshipDLR (Germany)en_US
dc.description.sponsorshipASI/INAF (Italy)en_US
dc.description.sponsorshipCICYT/MCYT (Spain)en_US
dc.description.sponsorshipAustrian Research Promotion Agency (FFG) through the ASAP initiative of the Austrian Federal Ministry for Transport, Innovation and Technology (BMVIT)en_US
dc.language.isoEnglishen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectstars: variables: t tauri, herbig ae/been_US
dc.subjectastrochemistryen_US
dc.subjectprotoplanetaryen_US
dc.subjectdisksen_US
dc.subjectherbig ae/be starsen_US
dc.subjectintermediate-mass starsen_US
dc.subjectmain-sequence starsen_US
dc.subjectmidinfrared molecular-emissionen_US
dc.subjectyoung circumstellar disksen_US
dc.subjectplanet-forming zonesen_US
dc.subjectiso-lws observationsen_US
dc.subjectt-tauri starsen_US
dc.subjecthd 100546en_US
dc.subjectorganic-moleculesen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleDIGIT Survey Of Far-Infrared Lines From Protoplanetary Disks I. Oi , Cii , Oh, H2O, And CH+en_US
dc.typeArticleen_US
dc.description.departmentAstronomyen_US
dc.identifier.doi10.1051/0004-6361/201321118en_US
dc.contributor.utaustinauthorEvans, Neal J.en_US
dc.contributor.utaustinauthorGreen, Joelen_US
dc.relation.ispartofserialAstronomy & Astrophysicsen_US


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