@prefix dcat: . @prefix dct: . @prefix foaf: . @prefix vcard: . @prefix xsd: . a dcat:Dataset ; dct:description """ Debris disks orbiting in the environment of nearby stars are a very important indicator of extrasolar planetary systems properties. From space and from the ground, current observational facilities enable a multi-wavelength determination of the disks structures and of the dust properties. This thesis addresses the topic of debris disks modelling, based on data from multiple instruments including first of all the Herschel and Hubble space telescopes, and the VLTI, CHARA and KIN infrared interferometers. My first research pro jects took place in the framework of two key programs from the Herschel Space Observatory dedicated to the study of circumstellar disks around nearby stars. As part of the GASPS pro ject, I obtained Herschel far-infrared spectro-photometric observations of HD 181327, a young (12+8−4 Myr) Sun-like star surrounded by a massive, 90 AU-wide debris belt, also imaged in scattered light by the Hubble Space Telescope. Proper determination of the belt geometry allows one to focus on modelling the dust properties. I used the GRaTer radiative transfer code to demonstrate that the system hosts a population of icy planetesimals that may be a source for the future delivery of water and volatiles onto forming terrestrial planets. I discuss additional results obtained with Herschel related to young debris disks, in particular HD 32297, and to faint Kuiper-Belt analogues. Exo-zodiacal disks (exozodis), those analogues to the Solar System Zodiacal cloud, represent a little known hot (or warm) counterpart of debris disks located close the habitable zone (inside of a few AUs). They are revealed by their near- to mid-infrared emission and can be assessed with the required accuracy and resolution with optical interferometers. In the case of the near edge-on star β Pictoris (12+8−4 Myr), I show that a significant fraction of the outer disk scatters light towards the small field-of-view of the interferometers; an inner hot component must nonetheless be invoked to explain the measured near-infrared excess. Based on the example of the star Vega (440 ± 40 Myr), I introduce a methodology to study inner dust disks and I show that hot exozodis are characterized by an abundance of submicron-sized grains, close to the star sublimation distance. From a theoretical point-of-view, the production mechanism for these small, unbound grains is not understood. I go into more details on the case of the Fomalhaut (440 ± 40 Ma) double-component (warm and hot) exozodiacal disk. I develop a new model for the calculation of the dust sublimation distances, and I address the various processes that can affect a dust grain in order to provide a framework for interpreting the exozodi: the hot exozodiacal disk may be the indirect signature of an asteroid belt with a particularly high dynamical activity. Lastly I draw up a summary of the properties of dusty debris disks and of what they can teach us when compared to the Solar System. I propose possible future research directions for further investigations of planetary systems and their dynamics. """ ; dct:identifier "NNT: 2013GRENY013" ; dct:issued "2026-05-06T05:26:19.505512"^^xsd:dateTime ; dct:language "fr" ; dct:modified "2026-05-06T05:26:19.505517"^^xsd:dateTime ; dct:publisher ; dct:title "Observations and modeling of planetary systems around nearby stars." ; dcat:contactPoint [ a vcard:Organization ; vcard:fn "CCSD" ] ; dcat:distribution ; dcat:keyword "astrophysics", "astrophysique", "debris-disks", "disques-de-debris", "dynamics", "dynamique", "formation-des-systemes-planetaires", "infoeu-reposemanticsdoctoralthesis", "modelisation-numerique", "numerical-modeling", "physcondcm-genphysics-physicscondensed-matter-cond-matother-cond-matother", "planetary-systems-formation", "radiative-transfer", "theses", "transfert-radiatif" ; dcat:landingPage . a dcat:Distribution ; dct:format "HTML" ; dct:issued "2026-05-06T05:26:19.510221"^^xsd:dateTime ; dct:modified "2026-05-06T05:26:19.488990"^^xsd:dateTime ; dct:title "Observations and modeling of planetary systems around nearby stars." ; dcat:accessURL . a foaf:Agent ; foaf:name "test_moissonnage_selune" . a foaf:Document .