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dc.contributor.authorHein Bertelsen, R.P.
dc.contributor.authorKamp, I.
dc.contributor.authorGoto, M.
dc.contributor.authorVan Der Plas, G.
dc.contributor.authorThi, W.-F.
dc.contributor.authorWaters, L.B.F.M.
dc.contributor.authorVan Den Ancker, M.E.
dc.contributor.authorWoitke, P.
dc.date.accessioned2014-08-29T08:31:08Z
dc.date.available2014-08-29T08:31:08Z
dc.date.issued2014-01-14
dc.identifier.citationHein Bertelsen , R P , Kamp , I , Goto , M , Van Der Plas , G , Thi , W-F , Waters , L B F M , Van Den Ancker , M E & Woitke , P 2014 , ' CO ro-vibrational lines in HD 100546 A search for disc asymmetries and the role of fluorescence ' , Astronomy & Astrophysics , vol. 561 , A102 . https://doi.org/10.1051/0004-6361/201322574en
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 144228116
dc.identifier.otherPURE UUID: d0f0593a-93bb-4c82-9103-e46177128992
dc.identifier.otherScopus: 84892376216
dc.identifier.otherWOS: 000330584000102
dc.identifier.urihttps://hdl.handle.net/10023/5286
dc.descriptionI.K., W.F.T., and P.W. acknowledge funding from the EU FP7-2011 under Grant Agreement no. 284405 (PERG06-GA-2009-256513). G.v.d.P. acknowledges support from the Millennium Science Initiative (Chilean Ministry of Economy), through grant “Nucleus P10-022-F”.en
dc.description.abstractAims. We have studied the emission of CO ro-vibrational lines in the disc around the Herbig Be star HD 100546 to determine physical properties, disc asymmetries, the CO excitation mechanism, and the spatial extent of the emission, with the final goal of using the CO ro-vibrational lines as a diagnostic to understand inner disc structure in the context of planet formation. Methods. High-spectral-resolution infrared spectra of CO ro-vibrational emission at eight different position angles were taken with the CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) at the Very Large Telescope (VLT). From these spectra flux tables, line profiles for individual CO ro-vibrational transitions, co-added line profiles, and population diagrams were produced. We have investigated variations in the line profile shapes and line strengths as a function of slit position angle. We used the thermo-chemical disc modelling code ProDiMo based on the chemistry, radiation field, and temperature structure of a previously published model for HD 100546. We calculated line fluxes and profiles for the whole set of observed CO ro-vibrational transitions using a large CO model molecule that includes the lowest two electronic states, each with 7 vibrational levels and within them 60 rotational levels. Comparing observations and the model, we investigated the possibility of disc asymmetries, the excitation mechanism (UV fluorescence), the geometry, and physical conditions of the inner disc. Results. The observed CO ro-vibrational lines are largely emitted from the inner rim of the outer disc at 10-13 AU. The line shapes are similar for all v levels and line fluxes from all vibrational levels vary only within one order of magnitude. All line profile asymmetries and variations can be explained with a symmetric disc model to which a slit correction and pointing offset is applied. Because the angular size of the CO emitting region (10-13 AU) and the slit width are comparable the line profiles are very sensitive to the placing of the slit. The model reproduces the line shapes and the fluxes of the v = 1-0 lines as well as the spatial extent of the CO ro-vibrational emission. It does not reproduce the observed band ratios of 0.5-0.2 with higher vibrational bands. We find that lower gas volume densities at the surface of the inner rim of the outer disc can make the fluorescence pumping more efficient and reproduce the observed band ratios.
dc.format.extent20
dc.language.isoeng
dc.relation.ispartofAstronomy & Astrophysicsen
dc.rights© ESO, 2014en
dc.subjectProtoplanetary disksen
dc.subjectLine: profilesen
dc.subjectStars: individual: HD 100546en
dc.subjectStars: variables: T Taurien
dc.subjectCircumstellar matteren
dc.subjectStars: variables: Herbig Ae/Been
dc.subjectQB Astronomyen
dc.subject.lccQBen
dc.titleCO ro-vibrational lines in HD 100546 A search for disc asymmetries and the role of fluorescenceen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.identifier.doihttps://doi.org/10.1051/0004-6361/201322574
dc.description.statusPeer revieweden
dc.identifier.urlhttp://www.scopus.com/inward/record.url?eid=2-s2.0-84892376216&partnerID=8YFLogxKen
dc.identifier.urlhttp://www.aanda.org/articles/aa/olm/2014/01/aa22574-13/aa22574-13.htmlen


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