Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Protoplanetary disks"”.
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High-resolution studies of protoplanetary disks
… mid-IR, mm) for previously unknown circumstellar disks and a study of those disk candidate objects which are not yet well characterised in the literature. 22 candidate stars, most of these constituting known exoplanet systems, were examined for circumstellar material using the Adaptive Optics …
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Hydrodynamical simulations of dust traps in protoplanetary disks
Las teorías actuales de formación planetaria concuerdan que los planetas se forman dentro de discos de gas y polvo alrededor de una estrella jóven. Sin embargo, no es claro cuál es el mecanismo detrás de la formación planetaria. Entre los mecanismos propuestos podemos encontrar que se podrían …
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OBSERVATIONAL CONSTRAINTS OF THE INTERACTION BETWEEN PLANETS AND PROTOPLANETARY DISKS
… process, emerging from the material within the protoplanetary disk surrounding the young protostar. Interactions between these newly formed planets and the disk create observable effects on the disk itself, which can be detected in the sub-millimeter to centimeter wavelength range through …
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A Meshless Method for Magnetohydrodynamics and Applications to Protoplanetary Disks
… in magnetorotationally turbulent regions of protoplanetary disks. This is a possible local mechanism for the melting of chondrules and the formation of other high-temperature materials in protoplanetary disks.
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Characterizing sub-mm observations of protoplanetary disks at super-resolution scales
… span Gyr of evolution, from their formation in protoplanetary disks and continued growth in debris disks to their dynamical evolution in exoplanetary systems and ultimate accretion onto white dwarfs. Measurements in each of these eras can be used to inform study in the others. Interferometry …
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Mass Assembly in Protoplanetary Disks: Polarimetry as a Probe of Dust Growth and Accretion
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-04-12 without embargo terms
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Probing giant-planet forming zones around Solar-like stars with CO
Protoplanetary disks are dusty disks around young stars where planets are formed. The evolution and composition of protoplanetary disks determine the time, environments and materials available for planet formation. However fundamental properties of protoplanetary disks such as mass, composition, …
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Streaming Instabilities in Class 0/I Disks
<p>While it is clear that planets form in protoplanetary disks, fragmentation and the radial drift of pebbles inhibit the growth of grains to planetesimals. To overcome these barriers, effective localized dust clumping on a short enough time scale is required. One promising solution to this problem …
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Describing protostellar disk structure in Ophiuchus
Young forming stars host circumstellar disks of dust and gas. High-resolution, millimeter observations of disks at the protoplanetary stage reveal substructures such as gaps, rings, arcs, spirals, and cavities. These structures are often attributed to disturbances from young, newly formed planets …
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Collisional and structural properties of water ice in planet-forming regions
… form by dust aggregation from the material of protoplanetary disks, with micron-sized particles sticking together by van der Waals forces and kilometre-sized particles sticking together due to gravity. The process of growth between millimetre and kilometre sizes is yet to be explained, despite …
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CREATING TEST MECHANISMS FOR SILICON SUBSTRATE BASED (SSB) DEVICES FOR USE IN FAR-IR TO MILLIMETER ASTROPHYSICAL SPECTROSCOPY
… instrument should detect while searching for protoplanetary disks. The next describes the development and laboratory testing of the VIPA instrument. POEMM will use a VIPA to spectrally resolve the: [OI] fine-structure line at 63 um, HD J=1-0 and J=2-1 rotational lines at 112 and 56 um, H2O …
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Planetesimal and Protoplanet Dynamics in a Turbulent Protoplanetary Disk
In a young protoplanetary disk, planetary objects undergo orbital migration due to the gravitational torques exerted by their surrounding gas. It has been an outstanding issue that an earth-sized planet embedded in a gas-rich environment may rapidly migrate into its host star. In this dissertation, …
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Analysis of Molecular Variability Due to Accretion Bursts in the Protoplanetary Disk of Ex Lup as Observed with the James Webb Space Telescope
Protoplanetary disks are structures that form around a pre-main sequence star as a result of conservation of angular momentum during collapse of dense cores in star-forming regions. They accrete gas onto the central proto-star, and are the sites of planet formation. Early in their lifetime, disk …
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Solving the N-body problem in astrophysics
… problems include open and globular clusters and protoplanetary disks during the stage, typically lasting hundreds of Myrs, when planetary embryos collide and merge. In the first part of this Thesis, I develop new symplectic integrators which provide a solution for the N-body problem. The …
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Probing planetary system histories via observations, experiments, and modelling of circumstellar gas and dust
Circumstellar disks of gas and dust are integral parts of planetary systems from formation to maturation. Protoplanetary disks, the name for circumstellar material at the earliest stages of a stellar lifetime, provide key information about the formation processes of planets, and therefore of the …
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Probing planetary disks: from birth to protoplanets
Protoplanetary disks set the physical and chemical conditions for the planets that will eventually form inside of them. While the exact details of the process remain a large area of research, it is the gas and dust in these disks that will grow into planets. By the Class II phase of a protostar’s …
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Spectropolarimetry of epsilon Aurigae: Probing Stellar and Disk Atmospheres
… evolution significant to our understanding of protoplanetary disks now seen in many star systems. Lastly, the project considers radiative transfer of polarized light that contributes to diverse fields such as atmospheric studies of exoplanets.</p> <p>My objective is to understand the …
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Shearing waves and the MRI dynamo in stratified accretion discs
Accretion discs efficiently transport angular momentum by a wide variety of as yet imperfectly understood mechanisms, with profound implications for the disc lifetime and planet formation. We discuss two different methods of angular momentum transport: first, generation of acoustic waves by mixing …
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High-resolution studies of exoplanetesimal belt formation and evolution
Stars are born with gas-rich protoplanetary discs that typically survive for a few Myr before dispersing, after which they are left with the planetary bodies that formed within the protoplanetary system: planets, and belts of planetesimals (km-sized rocky and icy bodies). Planetesimals within belts …
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Zonal flows in accretion discs and their role in gravito-turbulence
This thesis focuses on the evolution of zonal flows in self-gravitating accretion discs and their resulting effect on disc stability; it also studies the process of disc gravito-turbulence, with particular emphasis given to the way the turbulent state is able to extract energy from the background …