Parameterizing the dust around Herbig Ae/Be stars: Multiwavelength imaging, radiative transfer modeling, and near-infrared instrumentation

Herbig Ae/Be stars are considered the intermediate-mass analogs of the low-mass pre-main sequence T Tauri stars. Observations reveal that they are surrounded by dusty matter that may provide the solid-state material for building planets. Determining the dust parameters provides constraints for planet formation theory, and yields information about the matter around intermediate-mass stars as they approach the main sequence. In this dissertation, I present the results of a multiwavelength imaging and radiative transfer modeling study of Herbig Ae/Be stars, and a near-infrared instrumentation project, with the aim of parameterizing the dust in these systems.;The Hubble Space Telescope was used to search for optical light scattered by dust in a sample of young stars. This survey provided the first scattered-light image of the circumstellar environment around the Herbig Ae/Be star HD 97048. Structure is observed in the dust distribution similar to that seen in other Herbig Ae/Be systems. A ground-based near-infrared imaging study of Herbig Ae/Be candidates was also carried out. Photometry was collected for spectral energy distribution construction, and binary candidates were resolved. A mid-infrared image of the low-mass debris system, AU Microscopii, is presented, being relevant to the study of Herbig Ae/Be stars.;Detailed dust modeling of HD 97048 and HD 100546 was carried out with a two-component geometry consisting of a flared disk and an extended envelope. The models achieve a reasonable global fit to the spectral energy distributions, and produce images with the desired geometry. The disk midplane densities are found to go as r-0.5 and r -1.8, giving disk dust masses of 3.0 x 10-4 and 5.9 x 10-5 M⊙ for HD 97048 and HD 100546, respectively. A gas-to-dust mass ratio lower limit of 3.2 was calculated for HD 97048.;In order to advance the imaging capabilities available for observations of Herbig Ae/Be stars, I have participated in the development of the WIYN High Resolution Infrared Camera. The instrument operates in the near-infrared (∼0.8 -- 2.5 mum), includes 13 filters, and has a pixel size of ∼0.1&inches;, resulting in a field of view of ∼3' x 3'. An angular resolution of ∼0.25&inches; is anticipated. I provide an overview of the instrument, and report performance results with an emphasis on detector characterization.