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1. PENELLOPE: The ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES). I: Survey presentation and accretion properties of Orion OB1 and σ-Orionis

Author

J. Eislöffel, J. Campbell-White, Lynne A. Hillenbrand, I. Mendigutía, J. Alonso-Santiago, Davide Fedele, P. McGinnis, Ágnes Kóspál, Antonio Frasca, T. Thanathibodee, P. C. Schneider, Ł. Tychoniec, Sylvie Cabrit, M. Siwak, M. Koutoulaki, E. Sanchis, F. M. Walter, Giacomo Beccari, Andrea Banzatti, A. Sicilia-Aguilar, M. Gangi, Giovanni P. Rosotti, Myriam Benisty, H. M. J. Boffin, G. A. J. Hussain, C. Ginski, N. Arulanantham, S. Antoniucci, G. J. Herczeg, Jonathan Williams, C. Briceno, K. Maucó, Hans Moritz Günther, J. M. Alcalá, L. Venuti, M. M. James, Anna Miotello, R. Garcia Lopez, G. Zsidi, William J. Fischer, Nuria Calvet, Beate Stelzer, Péter Ábrahám, Elisabetta Rigliaco, Giuseppe Lodato, B. Ercolano, R. Mentel, Francesca Bacciotti, Elvira Covino, Teresa Giannini, J. Erkal, Rene D. Oudmaijer, Leonardo Testi, S. Facchini, Min Fang, A. Caratti o Garatti, Katia Biazzo, Lee Hartmann, E. Fiorellino, Jacco Vink, J. F. Gameiro, Jesús Hernández, K. Grankin, Carlo F. Manara, Massimo Robberto, Lorenzo Spina, Catherine Dougados, Catherine Espaillat, Deirdre Coffey, Jerome Bouvier, Brunella Nisini, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Low Energy Astrophysics (API, FNWI)

Subjects
Protoplanetary disks, Accretion, 010504 meteorology & atmospheric sciences, Continuum (design consultancy), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Planet, 0103 physical sciences, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stars: variables: T Tauri, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Complement (set theory), Line (formation), Physics, Herbig Ae/Be, Astronomy and Astrophysics, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Accretion disks, Stars: pre-main sequence, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The evolution of young stars and disks is driven by the interplay of several processes, notably accretion and ejection of material. Critical to correctly describe the conditions of planet formation, these processes are best probed spectroscopically. About five-hundred orbits of the Hubble Space Telescope (HST) are being devoted in 2020-2022 to the ULLYSES public survey of about 70 low-mass (M, Comment: Accepted for publication on Astronomy & Astrophysics. 15 pages + appendix, language edited version

Published
2021

2. I. Line profiles, physical conditions, and H 2 O abundance

Author

L. E. Kristensen, E. F. van Dishoeck, J. C. Mottram, A. Karska, U. A. Yıldız, E. A. Bergin, P. Bjerkeli, S. Cabrit, S. Doty, N. J. Evans, A. Gusdorf, D. Harsono, G. J. Herczeg, D. Johnstone, J. K. Jørgensen, T. A. van Kempen, J.-E. Lee, S. Maret, M. Tafalla, R. Visser, S. F. Wampfler, Danish Meat Research Institute (DMRI), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], foreign laboratories (FL), CERN [Genève], Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), London South Bank University (LSBU), Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
stars: jets, [PHYS]Physics [physics], stars: winds, outflows, ISM: jets and outflows, stars: formation, astrochemistry, line: profiles, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

Context. Through spectrally unresolved observations of high-J CO transitions, Herschel Photodetector Array Camera and Spectrometer (PACS) has revealed large reservoirs of warm (300 K) and hot (700 K) molecular gas around low-mass protostars. The excitation and physical origin of this gas is still not understood. Aims. We aim to shed light on the excitation and origin of the CO ladder observed toward protostars, and on the water abundance in different physical components within protostellar systems using spectrally resolved Herschel-HIFI data. Methods. Observations are presented of the highly excited CO line J = 16–15 (Eup/kB = 750 K) with the Herschel Heterodyne Instrument for the Far Infrared (HIFI) toward a sample of 24 low-mass protostellar objects. The sources were selected from the Herschel “Water in Star-forming regions with Herschel” (WISH) and “Dust, Ice, and Gas in Time” (DIGIT) key programs. Results. The spectrally resolved line profiles typically show two distinct velocity components: a broad Gaussian component with an average FWHM of 20 km s-1 containing the bulk of the flux, and a narrower Gaussian component with a FWHM of 5 km s-1 that is often offset from the source velocity. Some sources show other velocity components such as extremely-high-velocity features or “bullets”. All these velocity components were first detected in H2O line profiles. The average rotational temperature over the entire profile, as measured from comparison between CO J = 16–15 and 10–9 emission, is ~300 K. A radiative-transfer analysis shows that the average H2O/CO column-density ratio is ~0.02, suggesting a total H2O abundance of ~2 × 10-6, independent of velocity. Conclusions. Two distinct velocity profiles observed in the HIFI line profiles suggest that the high-J CO ladder observed with PACS consists of two excitation components. The warm PACS component (300 K) is associated with the broad HIFI component, and the hot PACS component (700 K) is associated with the offset HIFI component. The former originates in either outflow cavity shocks or the disk wind, and the latter in irradiated shocks. The low water abundance can be explained by photodissociation. The ubiquity of the warm and hot CO components suggest that fundamental mechanisms govern the excitation of these components; we hypothesize that the warm component arises when H2 stops being the dominant coolant. In this scenario, the hot component arises in cooling molecular H2-poor gas just prior to the onset of H2 formation. High spectral resolution observations of highly excited CO transitions uniquely shed light on the origin of warm and hot gas in low-mass protostellar objects.

Published
2017
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3. Resolved gas cavities in transitional disks inferred from CO isotopologs with ALMA

Author

Tim A. van Kempen, G. J. Herczeg, Ewine F. van Dishoeck, Nienke van der Marel, Sean M. Andrews, Anna Miotello, Klaus M. Pontoppidan, and Simon Bruderer

Subjects
Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010504 meteorology & atmospheric sciences, Drop (liquid), FOS: Physical sciences, Astronomy and Astrophysics, Trapping, Astrophysics, Spatial distribution, 01 natural sciences, Submillimeter Array, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Planet, 0103 physical sciences, Isotopologue, Millimeter, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

Transitional disks around young stars are promising candidates to look for recently formed, embedded planets. Planet-disk interaction models predict that planets clear a gap in the gas while trapping dust at larger radii. Other physical mechanisms could be responsible for cavities as well. Previous observations have revealed that gas is still present inside these cavities, but the spatial distribution of this gas remains uncertain. We present high spatial resolution observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of 13CO and C18O lines of four well-studied transitional disks. The observations are used to set constraints on the gas surface density, specifically cavity size and density drop inside the cavity. The physical-chemical model DALI is used to analyze the gas images of SR21, HD135344B, DoAr44 and IRS48. The main parameters of interest are the size, depth and shape of the gas cavity. CO isotope-selective photodissociation is included to properly constrain the surface density in the outer disk from C18O emission. The gas cavities are up to 3 times smaller than those of the dust in all four disks. Model fits indicate that the surface density inside the gas cavities decreases by a factor of 100-10000 compared with the surface density profile derived from the outer disk. A comparison with an analytical model of gap depths by planet-disk interaction shows that the disk viscosities are likely low, with a, Accepted by A&A; version after language-editing

Published
2016

4. [O I] 63 μ m JETS IN CLASS 0 SOURCES DETECTED BY HERSCHEL

Author

E. F. van Dishoeck, Claudio Codella, S. Antoniucci, G. J. Herczeg, Sylvie Cabrit, G. Santangelo, Lars E. Kristensen, Teresa Giannini, David A. Neufeld, Christopher J. Davis, Brunella Nisini, J. Eislöffel, INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), foreign laboratories (FL), CERN [Genève], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Thüringer Landessternwarte Tautenburg (TLS), Danish Meat Research Institute (DMRI), Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], Leiden Observatory [Leiden], Universiteit Leiden [Leiden], École normale supérieure - Paris (ENS-PSL), and Universiteit Leiden

Subjects
Physics, Mass flux, [PHYS]Physics [physics], Jet (fluid), 010504 meteorology & atmospheric sciences, Accretion (meteorology), Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Redshift, Luminosity, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, Outflow, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation)
Abstract

We present Herschel PACS mapping observations of the [O i] 63 μm line toward protostellar outflows in the L1448, NGC 1333-IRAS4, HH 46, BHR 71, and VLA 1623 star-forming regions. We detect emission spatially resolved along the outflow direction, which can be associated with a low-excitation atomic jet. In the L1448-C, HH 46 IRS, and BHR 71 IRS1 outflows this emission is kinematically resolved into blue- and redshifted jet lobes, having radial velocities up to 200 km s-1. In the L1448-C atomic jet the velocity increases with the distance from the protostar, similarly to what is observed in the SiO jet associated with this source. This suggests that [O i] and molecular gas are kinematically connected and that the latter could represent the colder cocoon of a jet at higher excitation. Mass flux rates ({{\dot{M}}jet}(O i)) have been measured from the [O i] 63 μm luminosity adopting two independent methods. We find values in the range (1-4) × 10-7 {{M}☉ } yr-1 for all sources except HH 46, for which an order of magnitude higher value is estimated. {{\dot{M}}jet}(O i) are compared with mass accretion rates (\dot{M}acc) onto the protostar and with {{\dot{M}}jet} derived from ground-based CO observations. {{\dot{M}}jet}(O i)/\dot{M}acc ratios are in the range 0.05-0.5, similar to the values for more evolved sources. {{\dot{M}}jet}(O i) in HH 46 IRS and IRAS4A are comparable to {{\dot{M}}jet}(CO), while those of the remaining sources are significantly lower than the corresponding {{\dot{M}}jet}(CO). We speculate that for these three sources most of the mass flux is carried out by a molecular jet, while the warm atomic gas does not significantly contribute to the dynamics of the system.

Published
2015
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5. Far-infrared CO and H_2O emission in intermediate-mass protostars

Author

A. Fuente, G. J. Herczeg, M. Matuszak, Agata Karska, T. A. van Kempen, Łukasz Tychoniec, and Lars E. Kristensen

Subjects
Physics, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Rotational temperature, Context (language use), Astrophysics, Radiation, Luminosity, Astrophysics - Solar and Stellar Astrophysics, Far infrared, Space and Planetary Science, Protostar, Solar and Stellar Astrophysics (astro-ph.SR), Excitation
Abstract

Intermediate-mass young stellar objects (YSOs) provide a link to understand how feedback from shocks and UV radiation scales from low to high-mass star forming regions. Aims: Our aim is to analyze excitation of CO and H$_2$O in deeply-embedded intermediate-mass YSOs and compare with low-mass and high-mass YSOs. Methods: Herschel/PACS spectral maps are analyzed for 6 YSOs with bolometric luminosities of $L_\mathrm{bol}\sim10^2 - 10^3$ $L_\odot$. The maps cover spatial scales of $\sim 10^4$ AU in several CO and H$_2$O lines located in the $\sim55-210$ $\mu$m range. Results: Rotational diagrams of CO show two temperature components at $T_\mathrm{rot}\sim320$ K and $T_\mathrm{rot}\sim700-800$ K, comparable to low- and high-mass protostars probed at similar spatial scales. The diagrams for H$_2$O show a single component at $T_\mathrm{rot}\sim130$ K, as seen in low-mass protostars, and about $100$ K lower than in high-mass protostars. Since the uncertainties in $T_\mathrm{rot}$ are of the same order as the difference between the intermediate and high-mass protostars, we cannot conclude whether the change in rotational temperature occurs at a specific luminosity, or whether the change is more gradual from low- to high-mass YSOs. Conclusions: Molecular excitation in intermediate-mass protostars is comparable to the central $10^{3}$ AU of low-mass protostars and consistent within the uncertainties with the high-mass protostars probed at $3\cdot10^{3}$ AU scales, suggesting similar shock conditions in all those sources., Comment: Accepted to Astronomy & Astrophysics. 4 pages, 5 figures, 3 tables

Published
2015

6. Resolving the shocked gas in HH54 with Herschel: CO line mapping at high spatial and spectral resolution

Author

S. Cabrit, G. J. Herczeg, G. Olofsson, Per Bjerkeli, Kay Justtanont, Mario Tafalla, Bengt Larsson, René Liseau, G. Santangelo, C. Brinch, John H. Black, Lars E. Kristensen, Brunella Nisini, and M. Benedettini

Subjects
Shock wave, Physics, 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Space observatory, On board, Atmospheric radiative transfer codes, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Chamaeleon, Emission spectrum, Spectral resolution, 010303 astronomy & astrophysics
Abstract

The HH54 shock is a Herbig-Haro object, located in the nearby Chamaeleon II cloud. Observed CO line profiles are due to a complex distribution in density, temperature, velocity, and geometry. Resolving the HH54 shock wave in the far-infrared cooling lines of CO constrain the kinematics, morphology, and physical conditions of the shocked region. We used the PACS and SPIRE instruments on board the Herschel space observatory to map the full FIR spectrum in a region covering the HH54 shock wave. Complementary Herschel-HIFI, APEX, and Spitzer data are used in the analysis as well. The observed features in the line profiles are reproduced using a 3D radiative transfer model of a bow-shock, constructed with the Line Modeling Engine code (LIME). The FIR emission is confined to the HH54 region and a coherent displacement of the location of the emission maximum of CO with increasing J is observed. The peak positions of the high-J CO lines are shifted upstream from the lower J CO lines and coincide with the position of the spectral feature identified previously in CO(10-9) profiles with HIFI. This indicates a hotter molecular component in the upstream gas with distinct dynamics. The coherent displacement with increasing J for CO is consistent with a scenario where IRAS12500-7658 is the exciting source of the flow, and the 180 K bow-shock is accompanied by a hot (800 K) molecular component located upstream from the apex of the shock and blueshifted by -7 km s$^{-1}$. The spatial proximity of this knot to the peaks of the atomic fine-structure emission lines observed with Spitzer and PACS ([OI]63, 145 $\mu$m) suggests that it may be associated with the dissociative shock as the jet impacts slower moving gas in the HH54 bow-shock., Comment: 6 pages, 5 figures

Published
2014

7. THE WATER ABUNDANCE BEHIND INTERSTELLAR SHOCKS: RESULTS FROM HERSCHEL /PACS AND SPITZER /IRS OBSERVATIONS OF H 2 O, CO, AND H 2

Author

G. J. Herczeg, Antoine Gusdorf, Ewine F. van Dishoeck, Brunella Nisini, Mario Tafalla, Gary J. Melnick, Lars E. Kristensen, Volker Ossenkopf, Rolf Güsten, David A. Neufeld, Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), DAIMI (DAIMI), DAIMI, Leiden Observatory [Leiden], Universiteit Leiden [Leiden], and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Shock wave, 010504 meteorology & atmospheric sciences, Hydrogen, Astrophysics::High Energy Astrophysical Phenomena, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, Spectral line, Ion, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Line (formation), Physics, Spectrometer, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Supernova, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]
Abstract

We have investigated the water abundance in shock-heated molecular gas, making use of $Herschel$ measurements of far-infrared CO and H$_2$O line emissions in combination with $Spitzer$ measurements of mid-IR H$_2$ rotational emissions. We present far-infrared line spectra obtained with $Herschel$'s PACS instrument in range spectroscopy mode towards two positions in the protostellar outflow NGC 2071 and one position each in the supernova remnants W28 and 3C391. These spectra provide unequivocal detections, at one or more positions, of 12 rotational lines of water, 14 rotational lines of CO, 8 rotational lines of OH (4 lambda doublets), and 7 fine-structure transitions of atoms or atomic ions. We first used a simultaneous fit to the CO line fluxes, along with H$_2$ rotational line fluxes measured previously by $Spitzer$, to constrain the temperature and density distribution within the emitting gas; and we then investigated the water abundances implied by the observed H$_2$O line fluxes. The water line fluxes are in acceptable agreement with standard theoretical models for nondissociative shocks that predict the complete vaporization of grain mantles in shocks of velocity $v \sim 25$ km/s, behind which the characteristic gas temperature is $\sim 1300$ K and the H$_2$O/CO ratio is 1.2, Comment: 42 pages, 15 figures, accepted for publication in the Astrophysical Journal

Published
2014
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8. Water in star forming regions with Herschel (WISH) III. Far-infrared cooling lines in low-mass young stellar objects

Author

Agata Karska, Javier R. Goicoechea, Mario Tafalla, Jes K. Jørgensen, S. F. Wampfler, G. J. Herczeg, Arnold O. Benz, Friedrich Wyrowski, Davide Fedele, Paola Caselli, E. A. Bergin, Michiel R. Hogerheijde, Umut A. Yildiz, Lars E. Kristensen, Sandra L. Doty, I. San-Jose Garcia, F. F. S. van der Tak, P. Sniady, E. F. van Dishoeck, R. Visser, D. Johnstone, Brunella Nisini, René Liseau, Fabrice Herpin, S. Bruderer, foreign laboratories (FL), CERN [Genève], Max-Planck-Institut für Extraterrestrische Physik (MPE), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Institute of Astronomy [ETH Zürich], Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, INAF - Osservatorio Astrofisico di Arcetri (OAA), FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, BC V9E 2E7 Canada, Natl Res Council Canada, Herzberg Inst Astrophys, Victoria, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG ), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), and Kapteyn Astronomical Institute

Subjects
astro-ph.SR, 010504 meteorology & atmospheric sciences, astro-ph.GA, Young stellar object, FOS: Physical sciences, Astrophysics, SUBMILLIMETER CONTINUUM OBSERVATIONS, PHYSICAL STRUCTURE, 01 natural sciences, 7. Clean energy, COLOGNE DATABASE, Spectral line, J CO OBSERVATIONS, Luminosity, INTERSTELLAR SHOCKS, Far infrared, NGC 1333, 0103 physical sciences, OUTFLOW L1157, Protostar, Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Line (formation), Envelope (waves), Physics, infrared: ISM, stars: protostars, astrochemistry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, THERMAL BALANCE, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, molecular processes, ISM: jets and outflows, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MOLECULAR CLOUDS, PROTOSTELLAR SHOCK L1157-B1, Low Mass, Galaxy Astrophysics
Abstract

(Abridged) Far-infrared Herschel-PACS spectra of 18 low-mass protostars of various luminosities and evolutionary stages are studied. We quantify their far-infrared line emission and the contribution of different atomic and molecular species to the gas cooling budget during protostellar evolution. We also determine the spatial extent of the emission and investigate the underlying excitation conditions. Most of the protostars in our sample show strong atomic and molecular far-infrared emission. Water is detected in 17 objects, including 5 Class I sources. The high-excitation H2O line at 63.3 micron is detected in 7 sources. CO transitions from J=14-13 up to 49-48 are found and show two distinct temperature components on Boltzmann diagrams with rotational temperatures of ~350 K and ~700 K. H2O has typical excitation temperatures of ~150 K. Emission from both Class 0 and I sources is usually spatially extended along the outflow direction but with a pattern depending on the species and the transition. The H2O line fluxes correlate strongly with those of the high-J CO lines, as well as with the bolometric luminosity and envelope mass. They correlate less strongly with OH and not with [OI] fluxes. The PACS data probe at least two physical components. The H2O and CO emission likely arises in non-dissociative (irradiated) shocks along the outflow walls with a range of pre-shock densities. Some OH is also associated with this component, likely resulting from H2O photodissociation. UV-heated gas contributes only a minor fraction to the CO emission observed by PACS, based on the strong correlation between the shock-dominated CO 24-23 line and the CO 14-13 line. [OI] and some of the OH emission probe dissociative shocks in the inner envelope. The total far-infrared cooling is dominated by H2O and CO, with [OI] increasing for Class I sources., Accepted for publication in A&A, 48 pages with appendix

Published
2013
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9. DIGIT survey of far-infrared lines from protoplanetary disks. I. [O i], [C ii], OH, H2O, and CH

Author

Joan Najita, Davide Fedele, J. Carr, Manuel Güdel, Colette Salyk, E. F. van Dishoeck, Th. Henning, Simon Bruderer, Jeroen Bouwman, Gwendolyn Meeus, Neal J. Evans, G. J. Herczeg, Joel D. Green, and UAM. Departamento de Física Teórica

Subjects
Protoplanetary disks, Astrochemistry, Variables: T Tauri [Stars], 010504 meteorology & atmospheric sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Far infrared, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation), Physics, Herbig Ae/Be, Física, Astronomy and Astrophysics, Wavelength, T Tauri star, Stars, 13. Climate action, Space and Planetary Science, Stars: Variables: T Tauri, Excitation, Main sequence
Abstract

Astronomy and Astrophysics 559 (2013): A77 reproduced with permission from Astronomy & Astrophysics, We present far-infrared (50-200 μm) 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: [O i], [C ii], CO, OH, H2O, CH+. The most common feature is the [O i]63 μm 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 1013 < NOH < 1016 cm-2, emitting radii 15 < r < 100 AU and excitation temperatures 100 < Tex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ≥ 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 (Tex ~ 100 K) and compact (r ~ 60 AU) emission in the case of HD 100546. Off-source [O i] emission is detected toward DG Tau, whose origin is likely the outflow associated with this source. The [C ii] emission is spatially extended in all sources where the line is detected. This suggests that not all [C ii] 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 ([O i]63 μm, [O i]145 μm, [C ii]) are analyzed with PDR models and require high gas density (n ≳ 105 cm-3) and high UV fluxes (G o ~ 103 - 107), consistent with a disk origin for the oxygen lines for most of the sources, Support for this work, part of the Herschel open time key project program, was provided by NASA through an award issued by the Jet Propulsion Laboratory, California Institute of Technology. We are grateful to the DIGIT team for stimulating discussions and scientific support. Astrochemistry in Leiden is supported by the Netherlands Research School for Astronomy (NOVA), by a Spinoza grant and grant 614.001.008 from the Netherlands Organisation for Scientific Research (NWO), and by the European Community’s Seventh Framework Programme FP7/2007−2013 under grant 238258 (LASSIE) and grant 291141 (CHEMPLAN). PACS has been developed by a consortium of institutes led by MPE (Germany) and including UVIE (Austria); KU Leuven, CSL, IMEC (Belgium); CEA, LAM (France); MPIA (Germany); INAF-IFSI/OAA/OAP/OAT, LENS, SISSA (Italy); IAC (Spain). This development has been supported by the funding agencies BMVIT (Austria), ESAPRODEX (Belgium), CEA/CNES (France), DLR (Germany), ASI/INAF (Italy), and CICYT/MCYT (Spain). The research of M.G. has been supported by the Austrian Research Promotion Agency (FFG) through the ASAP initiative of the Austrian Federal Ministry for Transport, Innovation and Technology (BMVIT)

Published
2013

10. The unusual protoplanetary disk around the T Tauri star ET Chamaeleontis

Author

Göran Sandell, Anthony G. A. Brown, I. de Gregorio-Monsalvo, Gaspard Duchêne, A. Ran Lyo, Wing-Fai Thi, N. Phillips, G. J. Herczeg, Inga Kamp, E. A. Bergin, B. Riaz, Francois Menard, Sean D. Brittain, I. Pascucci, W. R. F. Dent, Giambattista Aresu, Peter Woitke, A. Mora, and Astronomy

Subjects
INFRARED-EMISSION, Astrophysics, stars: pre-main sequence, Protoplanetary disk, 7. Clean energy, 01 natural sciences, Photometry (optics), DIRTY DUST GRAINS, INTERSTELLAR SILICATE MINERALOGY, RADIATION THERMOCHEMICAL MODELS, ETA-CHAMAELEONTIS, YOUNG STARS, PLANETARY-SYSTEMS, 0103 physical sciences, Radiative transfer, Emission spectrum, 010306 general physics, 010303 astronomy & astrophysics, Physics, stars: individual: ET Cha, astrochemistry, protoplanetary disks, GAS MASS, Astronomy and Astrophysics, T Tauri star, 13. Climate action, Space and Planetary Science, radiative transfer, MOLECULAR-HYDROGEN, Outflow, line: formation, MAIN-SEQUENCE STARS, Loss rate
Abstract

We present new continuum and line observations, along with modelling, of the faint (6-8) Myr old T Tauri star ET Cha belonging to the eta Chamaeleontis cluster. We have acquired Herschel/PACS photometric fluxes at 70 mu m and 160 mu m, as well as a detection of the [OI] 63 mu m fine-structure line in emission, and derived upper limits for some other far-IR OI, CII, CO and o-H2O lines. These observations were carried out in the frame of the open time key programme GASPS, where ETCha was selected as one of the science demonstration phase targets. The Herschel data is complemented by new simultaneous ANDICAM B-K photometry, new HST/COS and HST/STIS UV-observations, a non-detection of CO J = 3 -> 2 with APEX, re-analysis of a UCLES high-resolution optical spectrum showing forbidden emission lines like [OI] 6300 angstrom, [SII] 6731 angstrom and 6716 angstrom, and [NII] 6583 angstrom, and a compilation of existing broad-band photometric data. We used the thermo-chemical disk code ProDiMo and the Monte-Carlo radiative transfer code MCFOST to model the protoplanetary disk around ETCha. The paper also introduces a number of physical improvements to the ProDiMo disk modelling code concerning the treatment of PAH ionisation balance and heating, the heating by exothermic chemical reactions, and several non-thermal pumping mechanisms for selected gas emission lines. By applying an evolutionary strategy to minimise the deviations between model predictions and observations, we find a variety of united gas and dust models that simultaneously fit all observed line and continuum fluxes about equally well. Based on these models we can determine the disk dust mass with confidence, M-dust approximate to (2-5) x 10(-8) M-circle dot whereas the total disk gas mass is found to be only little constrained, M-gas approximate to (5 x 10(-5)-3 x 10(-3)) M-circle dot. Both mass estimates are substantially lower than previously reported. In the models, the disk extends from 0.022 AU (just outside of the co-rotation radius) to only about 10 AU, remarkably small for single stars, whereas larger disks are found to be inconsistent with the CO J = 3 -> 2 non-detection. The low velocity component of the [OI] 6300 angstrom emission line is centred on the stellar systematic velocity, and is consistent with being emitted from the inner disk. The model is also consistent with the line flux of H-2 v = 1 -> 0 S(1) at 2.122 mu m and with the [OI] 63 mu m line as seen with Herschel/PACS. An additional high-velocity component of the [OI] 6300 angstrom emission line, however, points to the existence of an additional jet/outflow of low velocity 40-65 km s(-1) with mass loss rate approximate to 10(-9) M-circle dot/yr. In relation to our low estimations of the disk mass, such a mass loss rate suggests a disk lifetime of only similar to 0.05-3 Myr, substantially shorter than the cluster age. If a generic gas/dust ratio of 100 was assumed, the disk lifetime would be even shorter, only similar to 3000 yrs. The evolutionary state of this unusual protoplanetary disk is discussed.

Published
2011
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11. First hyperfine structure resolved OH FIR spectrum of a star-forming region

Author

S. F., Wampfler, BRUDERER, S., L. E., Kristensen, E. A., Bergin, A. O., Benz, DISHOECK E. F., Van, G. J., Herczeg, DER TAK F. F. S., Van, J. R., Goicoechea, S. D., Doty, HERPIN, Fabrice, Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)

Subjects
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]
Abstract

International audience; Embedded protostars interact with their natal cloud through shocks and irradiation. The ambient interstellar medium warms up, allowing icy grain mantles to evaporate and making different chemical routes in the gas phase available. Water then becomes one of the most abundant molecular species in the gas phase. The Herschel key program 'Water in Star-Forming Regions with Herschel (WISH)' studies the excitation and chemistry of water around protostars. Hydroxyl (OH) is of the cornerstone species in the water chemistry network, because it is closely linked to both the formation and destruction of water through the OH + H2 leftrightarrow H2O + H reactions and photodissociation processes. This poster presents the first OH observation with resolved hyperfine structure at 163 μm of a star-forming region obtained using HIFI on Herschel. The OH triplet from the high-mass star-forming region W3 IRS5 is in emission, with the line profile revealing a narrow component on top of a broad feature. The broad component is attributed to outflow emission based on comparison with molecular lines of other species, whereas the narrow component is in agreement with radiative transfer results for a spherically symmetric envelope model. The resolved hyperfine structure allows us to constrain the excitation temperature and the OH column density in our models simultaneously. The derived OH/H2O ratios in the envelope are consistent with the current picture of the water chemistry. In the outer envelope (T < 100 K), where OH and H2O are released into the gas phase by photodesorption from the ice mantles of dust grains, we find a ratio of about unity. Laboratory work by Öberg et al. (2009) demonstrated that similar amounts of OH and water are released with an expected OH/H2O ratio of 0.5-1. This ratio is also in agreement with the theoretical work by Andersson & van Dishoeck (2008). In the inner envelope (T > 100 K), water is efficiently formed from OH and the OH/H2O ratio is therefore expected to drop significantly, which is consistent with the derived value of the order of 10-4. For the outflow, a lower limit of OH/H2O > 0.025 is obtained and can be explained with either a fast J-type shock or a slower UV irradiated C-type shock.

Published
2011

12. Herschel/HIFI spectroscopy of the intermediate mass protostar NGC7129 FIRS 2 [Letter]

Author

D. Johnstone, M. Fich, C. McCoey, T. A. van Kempen, A. Fuente, L. E. Kristensen, J. Cernicharo, P. Caselli, R. Visser, R. Plume, G. J. Herczeg, E. F. van Dishoeck, S. Wampfler, R. Bachiller, A. Baudry, M. Benedettini, E. Bergin, A. O. Benz, P. Bjerkeli, G. Blake, S. Bontemps, J. Braine, S. Bruderer, C. Codella, F. Daniel, A. M. di Giorgio, C. Dominik, S. D. Doty, P. Encrenaz, T. Giannini, J. R. Goicoechea, Th. de Graauw, F. Helmich, F. Herpin, M. R. Hogerheijde, T. Jacq, J. K. Jørgensen, B. Larsson, D. Lis, R. Liseau, M. Marseille, G. Melnick, D. Neufeld, B. Nisini, M. Olberg, B. Parise, J. Pearson, C. Risacher, J. Santiago-García, P. Saraceno, R. Shipman, M. Tafalla, F. van der Tak, F. Wyrowski, U. A. Yıldız, E. Caux, N. Honingh, W. Jellema, R. Schieder, D. Teyssier, N. Whyborn, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), Herschel Science Center [Madrid], European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Astronomy, Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, École normale supérieure - Paris (ENS Paris), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Consiglio Nazionale delle Ricerche (CNR), European Space Agency (ESA)-European Space Agency (ESA), and Low Energy Astrophysics (API, FNWI)

Subjects
STAR-FORMING REGIONS, stars: formation, PACS SPECTROSCOPY, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], astrochemistry, FOS: Physical sciences, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], YOUNG STELLAR OBJECTS, 01 natural sciences, EVOLUTION, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, EXCITATION, WATER, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), HIFI, HH 46, QB
Abstract

HERSCHEL-HIFI observations of water from the intermediate mass protostar NGC7129 FIRS 2 provide a powerful diagnostic of the physical conditions in this star formation environment. Six spectral settings, covering four H216O and two H218O lines, were observed and all but one H218O line were detected. The four H2 16 O lines discussed here share a similar morphology: a narrower, \approx 6 km/s, component centered slightly redward of the systemic velocity of NGC7129 FIRS 2 and a much broader, \approx 25 km/s component centered blueward and likely associated with powerful outflows. The narrower components are consistent with emission from water arising in the envelope around the intermediate mass protostar, and the abundance of H2O is constrained to \approx 10-7 for the outer envelope. Additionally, the presence of a narrow self-absorption component for the lowest energy lines is likely due to self-absorption from colder water in the outer envelope. The broader component, where the H2O/CO relative abundance is found to be \approx 0.2, appears to be tracing the same energetic region that produces strong CO emission at high J., 6 pages, 4 figures, accepted by A&A

Published
2010
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13. Water in massive star-forming regions: HIFI observations of W3 IRS5

Author

L. Chavarría, F. Herpin, T. Jacq, J. Braine, S. Bontemps, A. Baudry, M. Marseille, F. van der Tak, B. Pietropaoli, F. Wyrowski, R. Shipman, W. Frieswijk, E. F. van Dishoeck, J. Cernicharo, R. Bachiller, M. Benedettini, A. O. Benz, E. Bergin, P. Bjerkeli, G. A. Blake, S. Bruderer, P. Caselli, C. Codella, F. Daniel, A. M. di Giorgio, C. Dominik, S. D. Doty, P. Encrenaz, M. Fich, A. Fuente, T. Giannini, J. R. Goicoechea, Th. de Graauw, P. Hartogh, F. Helmich, G. J. Herczeg, M. R. Hogerheijde, D. Johnstone, J. K. Jørgensen, L. E. Kristensen, B. Larsson, D. Lis, R. Liseau, C. McCoey, G. Melnick, B. Nisini, M. Olberg, B. Parise, J. C. Pearson, R. Plume, C. Risacher, J. Santiago-García, P. Saraceno, J. Stutzki, R. Szczerba, M. Tafalla, A. Tielens, T. A. van Kempen, R. Visser, S. F. Wampfler, J. Willem, U. A. Yıldız, Astronomy, Low Energy Astrophysics (API, FNWI), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), SRON Netherlands Institute for Space Research (SRON), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB), École normale supérieure - Paris (ENS-PSL), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
010504 meteorology & atmospheric sciences, TRACERS, Astronomy, MODELS, FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, ISM: abundances, ABUNDANCES, RADIATIVE-TRANSFER, Abundance (ecology), 0103 physical sciences, Radiative transfer, Isotopologue, Spectral resolution, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, 0105 earth and related environmental sciences, Envelope (waves), Physics, radio lines: ISM, TRAPEZIUM, stars: formation, SPECTROSCOPY, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, extinction, PROTOSTARS, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: molecules, RATIOS, stars: massive, ENVELOPES, CONTINUUM, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Outflow, dust, dust, extinction
Abstract

We present Herschel observations of the water molecule in the massive star-forming region W3 IRS5. The o-H17O 110-101, p-H18O 111-000, p-H2O 22 202-111, p-H2O 111-000, o-H2O 221-212, and o-H2O 212-101 lines, covering a frequency range from 552 up to 1669 GHz, have been detected at high spectral resolution with HIFI. The water lines in W3 IRS5 show well-defined high-velocity wings that indicate a clear contribution by outflows. Moreover, the systematically blue-shifted absorption in the H2O lines suggests expansion, presumably driven by the outflow. No infall signatures are detected. The p-H2O 111-000 and o-H2O 212-101 lines show absorption from the cold material (T ~ 10 K) in which the high-mass protostellar envelope is embedded. One-dimensional radiative transfer models are used to estimate water abundances and to further study the kinematics of the region. We show that the emission in the rare isotopologues comes directly from the inner parts of the envelope (T > 100 K) where water ices in the dust mantles evaporate and the gas-phase abundance increases. The resulting jump in the water abundance (with a constant inner abundance of 10^{-4}) is needed to reproduce the o-H17O 110-101 and p-H18O 111-000 spectra in our models. We estimate water abundances of 10^{-8} to 10^{-9} in the outer parts of the envelope (T < 100 K). The possibility of two protostellar objects contributing to the emission is discussed., Accepted for publication in the A&A HIFI special issue

Published
2010
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14. Sensitive limits on the abundance of cold water vapor in the DM Tau protoplanetary disk

Author

T. A. Bell, Per Bjerkeli, A. Baudry, E. F. van Dishoeck, Friedrich Wyrowski, J. Santiago-Garcia, Jeffrey K. J. Fogel, Christian Brinch, D. Johnstone, Rene Plume, Fabien Daniel, Christophe Risacher, S. Bruderer, David A. Neufeld, Steven D. Doty, R. Shipman, J. Stutzki, Paola Caselli, Olja Panić, G. J. Herczeg, A. Fuente, Aggm Tielens, J. R. Goicoechea, Michael Olberg, G. A. Blake, C. Codella, E. A. Bergin, M. Fich, Bengt Larsson, Th. de Graauw, Berengere Parise, René Liseau, Rafael Bachiller, M. Benedettini, Paul Hartogh, Brunella Nisini, J. C. Pearson, Ryszard Szczerba, Mario Tafalla, Jes K. Jørgensen, F. F. S. van der Tak, Umut A. Yildiz, Michiel R. Hogerheijde, T. A. van Kempen, M. Marseille, Carsten Dominik, Frank Helmich, J. Braine, P. J. Encrenaz, Arnold O. Benz, Sylvain Bontemps, Susanne F. Wampfler, Fabrice Herpin, C. McCoey, P. Saraceno, Lars E. Kristensen, R. Visser, Teresa Giannini, José Cernicharo, T. Jacq, Willem Jellema, Gary J. Melnick, A. M. di Giorgio, Dariusz C. Lis, Low Energy Astrophysics (API, FNWI), Astronomy, Kapteyn Astronomical Institute, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Civilisations atlantiques & Archéosciences (C2A), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ministère de la Culture et de la Communication (MCC)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), Université de Nantes (UN)-Université de Nantes (UN), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Harvard University-Smithsonian Institution, Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB), École normale supérieure - Paris (ENS-PSL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Smithsonian Institution-Harvard University [Cambridge], Université de Nantes - UFR Histoire, Histoire de l'Art et Archéologie (UFR HHAA), and Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS)-Ministère de la Culture et de la Communication (MCC)

Subjects
DESORPTION, Abundance (chemistry), [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, DUST, Astrophysics, Protoplanetary disk, 01 natural sciences, ISM: abundances, MOLECULES, PLANET-FORMING REGION, CIRCUMSTELLAR DISKS, 0103 physical sciences, H2O, SPECTRA, Solar and Stellar Astrophysics, Emission spectrum, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Spectrometer, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, protoplanetary disks, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: molecules, EVOLUTION, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, GAS, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Earth and Planetary Astrophysics, Water ice, Water vapor, Intensity (heat transfer), STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract

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., 5 pages, 3 figures. Accepted for publication in the Herschel HIFI special issue of A&A

Published
2010
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15. First results of the Herschel key program 'Dust, Ice and Gas In Time' (DIGIT): Dust and gas spectroscopy of HD 100546

Author

G. J. Herczeg, L.B.F.M. Waters, E. A. Bergin, J. H. Chen, Sébastien Maret, John H. Lacy, Joel D. Green, Johan Olofsson, L. Cieza, J. C. Augereau, Jes K. Jørgensen, Colette Salyk, B. Sturm, Rowin Meijerink, Manuel Güdel, Bruno Merín, G. A. Blake, E. F. van Dishoeck, Umut A. Yildiz, Th. Henning, R. Visser, A. Glassgold, Michiel R. Hogerheijde, C. Knez, T. A. van Kempen, Daniel T. Jaffe, Paul M. Harvey, C. Waelkens, Gwendolyn Meeus, G. D. Mulders, J. M. Brown, M. M. Dunham, Lars E. Kristensen, Jeong-Eun Lee, Jordy Bouwman, Carsten Dominik, Lee G. Mundy, Neal J. Evans, Bram Acke, Joan Najita, J. Carr, Klaus Pontoppidan, Hyun-Ku Kim, and Low Energy Astrophysics (API, FNWI)

Subjects
Physics, Young stellar object, Molecular cloud, FOS: Physical sciences, Rotational transition, Astronomy and Astrophysics, Astrophysics, Protoplanetary disk, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Radiative transfer, Emission spectrum, Forbidden mechanism, Spectroscopy, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Context. We present far-infrared spectroscopic observations, taken with the Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory, of the protoplanetary disk around the pre-main-sequence star HD 100546. These observations are the first within the DIGIT Herschel key program, which aims to follow the evolution of dust, ice, and gas from young stellar objects still embedded in their parental molecular cloud core, through the final pre-main-sequence phases when the circumstellar disks are dissipated.Aims. Our aim is to improve the constraints on temperature and chemical composition of the crystalline olivines in the disk of HD 100546 and to give an inventory of the gas lines present in its far-infrared spectrum.Methods. The 69 μm feature is analyzed in terms of position and shape to derive the dust temperature and composition. Furthermore, we detected 32 emission lines from five gaseous species and measured their line fluxes.Results. The 69 μm emission comes either from dust grains with ~70 K at radii larger than 50 AU, as suggested by blackbody fitting, or it arises from ~200 K dust at ~13 AU, close to the midplane, as supported by radiative transfer models. We also conclude that the forsterite crystals have few defects and contain at most a few percent iron by mass. Forbidden line emission from [C ii] at 157 μm and [O i] at 63 and 145 μm, most likely due to photodissociation by stellar photons, is detected. Furthermore, five H2O and several OH lines are detected. We also found high-J rotational transition lines of CO, with rotational temperatures of ~300 K for the transitions up to J = 22-21 and T ~ 800 K for higher transitions.

Published
2010

16. Dust, Ice, and Gas In Time (DIGIT) Herschel program first results: A full PACS-SED scan of the gas line emission in protostar DK Chamaeleontis

Author

Manuel Güdel, Michiel R. Hogerheijde, C. Knez, T. A. van Kempen, C. P. Dullemond, A. Glassgold, Daniel T. Jaffe, Neal J. Evans, Joel D. Green, J. K. Joergensen, J. C. Augereau, John H. Lacy, Klaus Pontoppidan, G. J. Herczeg, E. A. Bergin, J. H. Chen, J. Carr, G. D. Mulders, B. Sturm, Johan Olofsson, Jordy Bouwman, Rowin Meijerink, Bram Acke, Carsten Dominik, L. Cieza, Colette Salyk, Bruno Merín, Joan Najita, Umut A. Yildiz, R. Visser, Hyun-Ku Kim, Máté Ádámkovics, G. A. Blake, Lee G. Mundy, C. Waelkens, Jeong-Eun Lee, J. M. Brown, Lars E. Kristensen, L.B.F.M. Waters, Sébastien Maret, E. F. van Dishoeck, Th. Henning, Paul M. Harvey, Gwendolyn Meeus, M. M. Dunham, Low Energy Astrophysics (API, FNWI), Laboratoire d'Astrophysique de Grenoble (LAOG), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Continuum (design consultancy), ISO-LWS OBSERVATIONS, Flux, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, circumstellar matter, SPITZER C2D SURVEY, NEARBY, INTERSTELLAR CLOUDS, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, HERBIG AE, OUTFLOW, Emission spectrum, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), POPULATION, ComputingMilieux_MISCELLANEOUS, Line (formation), Physics, infrared: ISM, Solar mass, stars: formation, SPECTROSCOPY, stars: protostars, STAR, astrochemistry, Astronomy and Astrophysics, YOUNG STELLAR OBJECTS, Accretion (astrophysics), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Excited state, submillimeter: ISM, Astrophysics::Earth and Planetary Astrophysics
Abstract

DK Cha is an intermediate-mass star in transition from an embedded configuration to a star plus disk stage. We aim to study the composition and energetics of the circumstellar material during this pivotal stage. Using the Range Scan mode of PACS on the Herschel Space Observatory, we obtained a spectrum of DK Cha from 55 to 210 micron as part of the DIGIT Key Program. Almost 50 molecular and atomic lines were detected, many more than the 7 lines detected in ISO-LWS. Nearly the entire ladder of CO from J=14-13 to 38-37 (E_u/k = 4080 K), water from levels as excited as E_u/k = 843 K, and OH lines up to E_u/k = 290 K were detected. The continuum emission in our PACS SED scan matches the flux expected from a model consisting of a star, a surrounding disk of 0.03 Solar mass, and an envelope of a similar mass, supporting the suggestion that the object is emerging from its main accretion stage. Molecular, atomic, and ionic emission lines in the far-infrared reveal the outflow's influence on the envelope. The inferred hot gas can be photon-heated, but some emission could be due to C-shocks in the walls of the outflow cavity., Comment: 4 Page letter, To appear in A&A special issue on Herschel

Published
2010

17. Water abundances in high-mass protostellar envelopes: Herschel observations with HIFI

Author

M. G. Marseille, F. F. S. van der Tak, F. Herpin, F. Wyrowski, L. Chavarría, B. Pietropaoli, A. Baudry, S. Bontemps, J. Cernicharo, T. Jacq, W. Frieswijk, R. Shipman, E. F. van Dishoeck, R. Bachiller, M. Benedettini, A. O. Benz, E. Bergin, P. Bjerkeli, G. A. Blake, J. Braine, S. Bruderer, P. Caselli, E. Caux, C. Codella, F. Daniel, P. Dieleman, A. M. di Giorgio, C. Dominik, S. D. Doty, P. Encrenaz, M. Fich, A. Fuente, T. Gaier, T. Giannini, J. R. Goicoechea, Th. de Graauw, F. Helmich, G. J. Herczeg, M. R. Hogerheijde, B. Jackson, H. Javadi, W. Jellema, D. Johnstone, J. K. Jørgensen, D. Kester, L. E. Kristensen, B. Larsson, W. Laauwen, D. Lis, R. Liseau, W. Luinge, C. McCoey, A. Megej, G. Melnick, D. Neufeld, B. Nisini, M. Olberg, B. Parise, J. C. Pearson, R. Plume, C. Risacher, P. Roelfsema, J. Santiago-García, P. Saraceno, P. Siegel, J. Stutzki, M. Tafalla, T. A. van Kempen, R. Visser, S. F. Wampfler, U. A. Yıldız, Low Energy Astrophysics (API, FNWI), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, SRON Netherlands Institute for Space Research (SRON), Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Max-Planck-Institut für Radioastronomie (MPIFR), and Astronomy

Subjects
010504 meteorology & atmospheric sciences, Astronomy, FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: abundances, STAR-FORMATION, REGION, RADIATIVE-TRANSFER, Abundance (ecology), EXCITATION, 0103 physical sciences, Radiative transfer, H2O, Protostar, Absorption (electromagnetic radiation), 010303 astronomy & astrophysics, QB, 0105 earth and related environmental sciences, Envelope (waves), Line (formation), Physics, Line-of-sight, extinction, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Star formation, Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, MONTE-CARLO METHOD, PROTOSTARS, CORES, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, ISM: molecules, EVOLUTION, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, dust, extinction, dust, EMISSION, Galaxy Astrophysics
Abstract

We derive the dense core structure and the water abundance in four massive star-forming regions which may help understand the earliest stages of massive star formation. We present Herschel-HIFI observations of the para-H2O 1_11-0_00 and 2_02-1_11 and the para-H2-18O 1_11-0_00 transitions. The envelope contribution to the line profiles is separated from contributions by outflows and foreground clouds. The envelope contribution is modelled using Monte-Carlo radiative transfer codes for dust and molecular lines (MC3D and RATRAN), with the water abundance and the turbulent velocity width as free parameters. While the outflows are mostly seen in emission in high-J lines, envelopes are seen in absorption in ground-state lines, which are almost saturated. The derived water abundances range from 5E-10 to 4E-8 in the outer envelopes. We detect cold clouds surrounding the protostar envelope, thanks to the very high quality of the Herschel-HIFI data and the unique ability of water to probe them. Several foreground clouds are also detected along the line of sight. The low H2O abundances in massive dense cores are in accordance with the expectation that high densities and low temperatures lead to freeze-out of water on dust grains. The spread in abundance values is not clearly linked to physical properties of the sources., Comment: 8 pages, 5 figures, accepted for publication the 15/07/2010 by Astronomy&Astrophysics as a letter in the Herschel-HIFI special issue

Published
2010
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18. Water in low-mass star-forming regions with Herschel . HIFI spectroscopy of NGC 1333

Author

Rafael Bachiller, Christophe Risacher, N. Whyborn, Steven D. Doty, A. Baudry, Per Bjerkeli, David A. Neufeld, Rene Plume, R. Shipman, F.-C. Liu, Pieter Dieleman, Sylvain Bontemps, Fabrice Herpin, E. F. van Dishoeck, M. Benedettini, Pieter R. Roelfsema, C. McCoey, José Cernicharo, Paola Caselli, J. Stutzki, Carsten Dominik, Paolo Saraceno, J. Braine, R. Visser, M. Fich, Susanne F. Wampfler, Frank Helmich, C. Codella, A. de Jonge, A. M. di Giorgio, Lars E. Kristensen, Friedrich Wyrowski, Geoffrey A. Blake, Teresa Giannini, E. Deul, Dariusz C. Lis, F. F. S. van der Tak, Volker Ossenkopf, J. Santiago-Garcia, Christian Brinch, M. Marseille, Th. de Graauw, Bengt Larsson, T. Jacq, Umut A. Yildiz, Mario Tafalla, A. Fuente, Jes K. Jørgensen, Arnold O. Benz, Fabien Daniel, Gary J. Melnick, S. Bruderer, Berengere Parise, Brunella Nisini, P. J. Encrenaz, Michiel R. Hogerheijde, T. A. van Kempen, René Liseau, D. A. Beintema, D. Johnstone, Aggm Tielens, J. R. Goicoechea, Michael Olberg, Michael J. Kaufman, J. C. Pearson, G. J. Herczeg, E. A. Bergin, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Laboratoire Optimisation de la Conception et Ingénierie de l'Environnement (LOCIE), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), INAF - Osservatorio Astronomico di Roma (OAR), Onsala Space Observatory, Chalmers University of Technology [Göteborg], ESO, European Southern Observatory (ESO), Istituto di Fisica dello Spazio Interplanetario (IFSI), Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Radioastronomie (MPIFR), Astronomy, Low Energy Astrophysics (API, FNWI), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB), Harvard University-Smithsonian Institution, École normale supérieure - Paris (ENS-PSL), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)

Subjects
010504 meteorology & atmospheric sciences, Astronomy, Young stellar object, FOS: Physical sciences, PROTOSTELLAR ENVELOPES, Astrophysics, PHYSICAL STRUCTURE, 01 natural sciences, DISK, Abundance (ecology), 0103 physical sciences, Protostar, OUTFLOW, Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Envelope (waves), Line (formation), QB, Physics, stars: formation, astrochemistry, Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], NGC-1333 IRAS-4, PROTOSTARS, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: molecules, ISM: jets and outflows, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, VAPOR, ABUNDANCE, Outflow, SUBMILLIMETER, EMISSION, Low Mass, ISM: individual objects: NGC 1333
Abstract

'Water In Star-forming regions with Herschel' (WISH) is a key programme dedicated to studying the role of water and related species during the star-formation process and constraining the physical and chemical properties of young stellar objects. The Heterodyne Instrument for the Far-Infrared (HIFI) on the Herschel Space Observatory observed three deeply embedded protostars in the low-mass star-forming region NGC1333 in several H2-16O, H2-18O, and CO transitions. Line profiles are resolved for five H16O transitions in each source, revealing them to be surprisingly complex. The line profiles are decomposed into broad (>20 km/s), medium-broad (~5-10 km/s), and narrow (20 km/s), indicating that its physical origin is the same as for the broad H2-16O component. In one of the sources, IRAS4A, an inverse P Cygni profile is observed, a clear sign of infall in the envelope. From the line profiles alone, it is clear that the bulk of emission arises from shocks, both on small (, Accepted for publication in the A&A HIFI special issue

Published
2010
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19. DIGIT survey of far-infrared lines from protoplanetary disks I. [O I], [CII], OH, H2O, and CH+.

Author

Fedele, D., Bruderer, S., van Dishoeck, E. F., Carr, J., G. J. Herczeg, Salyk, C., Evans II, N. J., Bouwman, J., Meeus, G., Henning, Th., Green, J., Najita, J. R., and Güdel, M.

Subjects
STAR observations, PROTOPLANETARY disks, ASTRONOMICAL surveys, SPECTRAL lines, MOLECULAR astrophysics, ASTROCHEMISTRY
Abstract

We present far-infrared (50-200 μm) 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: [O I], [C II], CO, OH, H2O, CH+. The most common feature is the [O I] 63 μm 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 1013 < NOH < 1016 cm-2, emitting radii 15 < r < 100AU and excitation temperatures 100 < Tex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ⩾ 1010 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 (Tex ~ 100K) and compact (r ~ 60AU) emission in the case of HD 100546. Off-source [O I] 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 ([O I] 63 μm, [O I] 145 μm, [CII]) are analyzed with PDR models and require high gas density (n ⩾ 105 cm-3) and high UV fluxes (Go ~ 103-107), consistent with a disk origin for the oxygen lines for most of the sources. [ABSTRACT FROM AUTHOR]

Published
2013
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20. The ODYSSEUS Survey. Motivation and First Results: Accretion, Ejection, and Disk Irradiation of CVSO 109

Author

C. C. Espaillat, G. J. Herczeg, T. Thanathibodee, C. Pittman, N. Calvet, N. Arulanantham, K. France, Javier Serna, J. Hernández, Á. Kóspál, F. M. Walter, A. Frasca, W. J. Fischer, C. M. Johns-Krull, P. C. Schneider, C. Robinson, Suzan Edwards, P. Ábrahám, Min Fang, J. Erkal, C. F. Manara, J. M. Alcalá, E. Alecian, R. D. Alexander, J. Alonso-Santiago, Simone Antoniucci, David R. Ardila, Andrea Banzatti, M. Benisty, Edwin A. Bergin, Katia Biazzo, César Briceño, Justyn Campbell-White, L. Ilsedore Cleeves, Deirdre Coffey, Jochen Eislöffel, Stefano Facchini, D. Fedele, Eleonora Fiorellino, Dirk Froebrich, Manuele Gangi, Teresa Giannini, K. Grankin, Hans Moritz Günther, Zhen Guo, Lee Hartmann, Lynne A. Hillenbrand, P. C. Hinton, Joel H. Kastner, Chris Koen, K. Maucó, I. Mendigutía, B. Nisini, Neelam Panwar, D. A. Principe, Massimo Robberto, A. Sicilia-Aguilar, Jeff A. Valenti, J. Wendeborn, Jonathan P. Williams, Ziyan Xu, R. K. Yadav, ITA, USA, GBR, FRA, DEU, and HUN

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) Director's Discretionary Program of low-mass pre-main-sequence stars, coupled with forthcoming data from ALMA and JWST, will provide the foundation to revolutionize our understanding of the relationship between young stars and their protoplanetary disks. A comprehensive evaluation of the physics of disk evolution and planet formation requires understanding the intricate relationships between mass accretion, mass outflow, and disk structure. Here we describe the Outflows and Disks around Young Stars: Synergies for the Exploration of ULLYSES Spectra (ODYSSEUS) Survey and present initial results of the classical T Tauri Star CVSO 109 in Orion OB1b as a demonstration of the science that will result from the survey. ODYSSEUS will analyze the ULLYSES spectral database, ensuring a uniform and systematic approach in order to (1) measure how the accretion flow depends on the accretion rate and magnetic structures, (2) determine where winds and jets are launched and how mass-loss rates compare with accretion, and (3) establish the influence of FUV radiation on the chemistry of the warm inner regions of planet-forming disks. ODYSSEUS will also acquire and provide contemporaneous observations at X-ray, optical, NIR, and millimeter wavelengths to enhance the impact of the ULLYSES data. Our goal is to provide a consistent framework to accurately measure the level and evolution of mass accretion in protoplanetary disks, the properties and magnitudes of inner-disk mass loss, and the influence of UV radiation fields that determine ionization levels and drive disk chemistry., accepted to ApJ

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21. THE DEPLETION OF WATER DURING DISPERSAL OF PLANET-FORMING DISK REGIONS.

Author

K. M. Pontoppidan, A. Banzatti, C. Salyk, G. J. Herczeg, E. F. van Dishoeck, and G. A. Blake

Subjects
CIRCUMSTELLAR matter, ORIGIN of planets, PROTOPLANETARY disks, CRYOGENICS, SPECTROMETERS, GEOCHEMISTRY, NATURAL satellites, PLANETARY water
Abstract

We present a new velocity-resolved survey of 2.9 μm spectra of hot H2O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R ∼ 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9–33 μm that probe from the dust sublimation radius at ∼0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H2O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 μm spectra (R ), which probes molecular gaps in inner disks. We find that H2O emission disappears from 2.9 μm (hotter water) to 33 μm (colder water) as increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars of generally have inner gaps with depleted molecular gas content. We measure radial trends in H2O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05–20 au. We propose that JWST spectroscopy of molecular gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA. [ABSTRACT FROM AUTHOR]

Published
2017
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22. A STEEPER THAN LINEAR DISK MASS–STELLAR MASS SCALING RELATION.

Author

I. Pascucci, L. Testi, G. J. Herczeg, F. Long, C. F. Manara, N. Hendler, G. D. Mulders, S. Krijt, F. Ciesla, Th. Henning, S. Mohanty, E. Drabek-Maunder, D. Apai, L. Szűcs, G. Sacco, and J. Olofsson

Subjects
STELLAR mass, STELLAR density (Stellar population), SPATIAL ability, MILLIMETER astronomy, TAURUS (Astrology)
Abstract

The disk mass is among the most important input parameter for every planet formation model to determine the number and masses of the planets that can form. We present an ALMA 887 μm survey of the disk population around objects from ∼2 to 0.03 M⊙ in the nearby ∼2 Myr old Chamaeleon I star-forming region. We detect thermal dust emission from 66 out of 93 disks, spatially resolve 34 of them, and identify two disks with large dust cavities of about 45 au in radius. Assuming isothermal and optically thin emission, we convert the 887 μm flux densities into dust disk masses, hereafter Mdust. We find that the relation is steeper than linear and of the form Mdust ∝ (M*)1.3–1.9, where the range in the power-law index reflects two extremes of the possible relation between the average dust temperature and stellar luminosity. By reanalyzing all millimeter data available for nearby regions in a self-consistent way, we show that the 1–3 Myr old regions of Taurus, Lupus, and Chamaeleon I share the same relation, while the 10 Myr old Upper Sco association has a steeper relation. Theoretical models of grain growth, drift, and fragmentation reproduce this trend and suggest that disks are in the fragmentation-limited regime. In this regime millimeter grains will be located closer in around lower-mass stars, a prediction that can be tested with deeper and higher spatial resolution ALMA observations. [ABSTRACT FROM AUTHOR]

Published
2016
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23. DIGIT survey of far-infrared lines from protoplanetary disks I. [O I], [CII], OH, H2O, and CH+.

Author

Fedele, D., Bruderer, S., van Dishoeck, E. F., Carr, J., G. J. Herczeg, Salyk, C., Evans II, N. J., Bouwman, J., Meeus, G., Henning, Th., Green, J., Najita, J. R., and Güdel, M.

Subjects
*STAR observations, *PROTOPLANETARY disks, *ASTRONOMICAL surveys, *SPECTRAL lines, *MOLECULAR astrophysics, *ASTROCHEMISTRY
Abstract

We present far-infrared (50-200 μm) 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: [O I], [C II], CO, OH, H2O, CH+. The most common feature is the [O I] 63 μm 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 1013 < NOH < 1016 cm-2, emitting radii 15 < r < 100AU and excitation temperatures 100 < Tex < 400 K. We used the non-LTE code RADEX to verify the LTE assumption. High gas densities (n ⩾ 1010 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 (Tex ~ 100K) and compact (r ~ 60AU) emission in the case of HD 100546. Off-source [O I] 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 ([O I] 63 μm, [O I] 145 μm, [CII]) are analyzed with PDR models and require high gas density (n ⩾ 105 cm-3) and high UV fluxes (Go ~ 103-107), consistent with a disk origin for the oxygen lines for most of the sources. [ABSTRACT FROM AUTHOR]

Published
2013
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