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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 559492.0, MPI für Astronomie / Publikationen_mpia
First results of the Herschel key program ``Dust, Ice and Gas In Time'' (DIGIT): Dust and gas spectroscopy of HD 100546
Authors:Sturm, B.; Bouwman, J.; Henning, T.; Evans, N. J.; Acke, B.; Mulders, G. D.; Waters, L. B. F. M.; van Dishoeck, E. F.; Meeus, G.; Green, J. D.; Augereau, J. C.; Olofsson, J.; Salyk, C.; Najita, J.; Herczeg, G. J.; van Kempen, T. A.; Kristensen, L. E.; Dominik, C.; Carr, J. S.; Waelkens, C.; Bergin, E.; Blake, G. A.; Brown, J. M.; Chen, J. H.; Cieza, L.; Dunham, M. M.; Glassgold, A.; Güdel, M.; Harvey, P. M.; Hogerheijde, M. R.; Jaffe, D.; Jørgensen, J. K.; Knez, C.; Lacy, J. H.; Lee, J. E.; Maret, S.; Meijerink, R.; Merín, B.; Mundy, L.; Pontoppidan, K. M.; Visser, R.; Yíldíz, U. A.
Date of Publication (YYYY-MM-DD):2010
Journal Abbrev.:Astronomy and Astrophysics
Start Page:id.L129
Audience:Not Specified
Abstract / Description: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. <BR /> 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. <BR /> 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. <BR /> 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. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Free Keywords:stars: individual: HD 100546; infrared: general; stars: pre-main sequence; techniques: spectroscopic
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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