This thesis focusses on the temperature structure in protoplanetary disks. The relation between structures seen in the dust and gas-phase molecules is investigated. This is crucial to understand... Show moreThis thesis focusses on the temperature structure in protoplanetary disks. The relation between structures seen in the dust and gas-phase molecules is investigated. This is crucial to understand the chemical composition of the planet forming material as well as to quantify the amount of gas present in the disk, a crucial parameter to determine if planets are likely present in the disk. One of the important regions in the disk is the water snowline, the midplane location where water freezes-out onto the dust grains. In this thesis, chemical modelling is used to infer the snowline location in a hot disk. This result is confirmed in the next chapter by 2D imaging of the water snow surface, the 2D equivalent of the water snowline. Additionally, the temperature structure across transition disk cavities is investigated to determine the mass of the planets that may be carving that cavity. Finally, the relation between the structures traced in the gas by different molecules and the dust is investigated to show that the chemical composition at the location of the dust rings and dust trap in the HD 100546 and OPH-IRS 48 disks, respectively, are different than in the other disk regions. Show less
We have conducted a full spectral line survey of the 3-13 micron region of two massive protostars, AFGL 2591 and AFGL 2136, for the first time at high spectral resolution. Utilising SOFIA/EXES... Show moreWe have conducted a full spectral line survey of the 3-13 micron region of two massive protostars, AFGL 2591 and AFGL 2136, for the first time at high spectral resolution. Utilising SOFIA/EXES observations, combined with ground based observations from TEXES and iSHELL, many transitions of HCN, C2H2, NH3, CS, CO and H2O are observed, with all species observed to be in absorption. High temperatures (600 K) and abundances (1-10e-6 w.r.t H) of each species are derived. In this thesis, I will present the new insights into the physical conditions and chemical composition of the disks that these absorption lines probe. In particular, hundreds of ro-vibrational transitions of H2O are detected with EXES towards each object, and are linked to a disk wind in AFGL 2591. Column density variations of HCN and C2H2 in bands that probe the same lower level, across different wavelengths, are also discussed, supporting the location of this gas in the circumstellar disk of these protostars. Finally emission lines of HCN are discussed towards MonR2 IRS 3 and are consistent with an origin in a circumstellar disk, or also possibly an expanding shell of gas, supported by P-Cygni profiles of CO lines. Show less
