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dc.contributor.advisorWoitke, Peter
dc.contributor.advisorRice, Ken
dc.contributor.authorTilling, Ian
dc.date.accessioned2013-12-11T09:56:25Z
dc.date.available2013-12-11T09:56:25Z
dc.date.issued2013-11-28
dc.identifier.urihttp://hdl.handle.net/1842/8271
dc.description.abstractProtoplanetary discs set the initial conditions for planet formation. By combining observations with detailed modelling, it is possible to constrain the physics and chemistry in such discs. I have used the detailed thermo-chemical disc model ProDiMo to explore the characteristics of the gas in protoplanetary discs, particularly in Herbig Ae objects. I have assessed the ability of various observational data to trace the disc properties. This has involved a number of different approaches. Firstly I compute a series of disc models with increasing mass, in order to test the diagnostic powers of various emission lines, in particular as gas mass tracers. This approach is then expanded to a large multiparameter grid of ~ 10 5 disc models. I have helped to develop a tool for analysing and plotting the huge quantity of data presented by such a model grid. Following this approach I move on to a detailed study of the Herbig Ae star HD 163296, attempting to fit the large wealth of available observations simultaneously. These include new Herschel observations of the far-infrared emission lines, as well as interferometric CO observations and a large number of continuum data. This study addresses the topical issues of the disc gas/dust ratio, and the treatment of the disc outer edge. It explores the effects of dust settling, UV variability and stellar X-ray emission on the disc chemistry and line emission. There is possible evidence for gas-depletion in the disc of HD 163296, with the line emission enhanced by dust settling, which would indicate a later evolutionary stage for this disc than suggested by other studies. Finally, I work to improve the treatment of the gas heating/cooling balance in ProDiMo, by introducing a non-LTE treatment of the atomic hydrogen line transitions and bound-free continuum transitions. I explore the effects of this on the disc chemical and thermal structure, and assess its impact in terms of the observable quantities.en_US
dc.contributor.sponsorScience and Technology Facilities Council (STFC)en_US
dc.language.isoenen_US
dc.publisherThe University of Edinburghen_US
dc.relation.hasversionTilling et al., “Gas modelling in the disc of HD 163296”. In Astronomy& Astrophysics, 2011.en_US
dc.relation.hasversionKamp, Tilling, Woitke, Thi & Hogerheijde, “Radiation thermo-chemical models of protoplanetary disks: II. Line diagnostics”. In Astronomy & Astrophysics, 2010.en_US
dc.relation.hasversionWoitke, Pinte, Tilling et al., “Continuum and line modelling of discs around young stars - I. 300000 disc models for HERSCHEL/GASPS”. In Monthly Notices of the Royal Astronomical Society, 2010.en_US
dc.relation.hasversionKamp, Woitke, Pinte, Tilling et al., “Continuum and line modeling of disks around young stars II. Line diagnostics for GASPS from the DENT grid”. In Astronomy & Astrophysics, 2011.en_US
dc.relation.hasversionMathews et al., “GAS in Protoplanetary Systems (GASPS). I. First results”. In Astronomy & Astrophysics, 2010.en_US
dc.relation.hasversionPinte et al., “The Herschel view of GAS in Protoplanetary Systems (GASPS). First comparisons with a large grid of models”. In Astronomy & Astrophysics, 2010.en_US
dc.relation.hasversionThi et al., “Herschel-PACS observation of the 10 Myr old T Tauri disk TW Hya. Constraining the disk gas mass”. In Astronomy & Astrophysics, 2010.en_US
dc.relation.hasversionMeeus et al., “Gas in the protoplanetary disc of HD 169142: Herschel’s view”. In Astronomy & Astrophysics, 2010.en_US
dc.subjectprotoplanetary discsen_US
dc.subjectHerschel observationsen_US
dc.subjectfar-infrared emission linesen_US
dc.titlePhysics and chemistry of gas in discsen_US
dc.typeThesis or Dissertationen_US
dc.type.qualificationlevelDoctoralen_US
dc.type.qualificationnamePhD Doctor of Philosophyen_US


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