Observational appearance of debris disks
Debris disks are dusty circumstellar disks around main-sequence stars and natural by-products of the planet formation process. With an almost gas-free environment, dust-replenishing parent bodies orbit their host star and most likely continuously supply ﬁne dust through mutual collisions. Thus, debris disks comprise solids ranging from kilometer-sized planetesimals down to micrometer-sized dust. Due to the large surface to volume ratio, dust grains are efficient radiators of thermal re-emission and scatterers of incident radiation from the stellar source. Dust grains are, therefore, readily detectable in a planetary system. Consequently, debris disk observables mainly depend on dust properties and the disk structure, as well as stellar properties. In this dissertation, an observational appearance of debris disks is investigated. This allows the veriﬁcation of predictions made concerning the spatial structure, underlying dynamical processes, and optical properties of the dust in the debris disk system. In particular, the potential for multi-wavelength and spatially resolved observations in numerical studies are conducted to constrain the observational appearance of debris disks with the physical properties and dynamics of dust grains. To develop observational strategies of disk observations, a new tool has been developed for analytical modeling of debris disks and the interpretation of results from the collisional approach. The dependence of the observational appearance of debris disks on essential collisional parameters, such as the eccentricity of the parent belt, the dispersion of the eccentricities of parent belt bodies, and the critical speciﬁc energy for fragmentation of dust particles, is investigated. Furthermore, the feasibility of detecting water ice in typical debris disk systems, assuming various ice destruction mechanisms and dust mixtures with various internal structures, is investigated. Additionally, the multi-wavelength modeling of debris disks in η Chameleontis cluster is investigated to constrain the physical parameters and properties of the disks, such as the range of possible radial locations and total dust mass, based on observation from the APEX/LABOCA and the archival Gaia/DR2 data. Finally, a model based on a planetesimal mass distribution function is investigated to discuss the ﬂattening of the spectral energy distribution of HD 107146 at mm wavelength with the NIKA2 observation.
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