The formation of stars and planets happens over multiple scales, which can interact. In particular, planet formation happens in the dense, complex environment of star forming regions. This thesis... Show moreThe formation of stars and planets happens over multiple scales, which can interact. In particular, planet formation happens in the dense, complex environment of star forming regions. This thesis primarily explores the effects of high stellar density and presence of nearby massive stars (or a low density and absence of massive stars) on the evolution of protoplanetary disks, and their consequences for planet formation. Additionally, the dynamics of stellar feedback-driven shells is explored, and a novel operator splitting algorithm is introduced that allows for flexible coupling of a large number of physical models. Show less
Detecting planets during their formation stages is crucial for understanding the history and diversity of fully developed planetary systems like our own. However, observing young planets directly... Show moreDetecting planets during their formation stages is crucial for understanding the history and diversity of fully developed planetary systems like our own. However, observing young planets directly is challenging because they are often deeply embedded within their host protoplanetary discs, rich in gas and dust. To overcome this limitation, this thesis introduces a novel methodology for identifying coherent kinematic perturbations in discs induced by giant planets orbiting stars with a mass similar to that of the Sun. This approach not only allows us to investigate the presence of planets but also to determine their most likely radial and azimuthal positions in a statistically robust manner. Moreover, it offers the additional benefit of enabling a three-dimensional reconstruction of the physical and dynamical structure of these planet-forming environments by simultaneously modelling the emission of multiple molecular tracers.The methodology is applied to various protoplanetary discs observed using the world-class interferometer ALMA, revealing a wide variety of kinematic and temperature features. These features include large-scale substructures with spiral and ring-like morphologies, as well as localised perturbations, some of which span coherently across the vertical extent of the disc indicating meridional circulation of material. Among the eight discs analysed, five exhibit signatures in the outer regions that could potentially be associated with massive embedded planets, suggesting that the interaction between discs and wide-orbit giant planets may represent a common early mechanism with a fundamental role in shaping the evolution of discs and, as a result, in the assembly and composition of planetary systems. 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
