The Circumstellar Dust Disk of HD 100546

We investigate the chemical composition, dust grain size range, and disk extent of the circumstellar disk surrounding the well-studied Herbig Ae star HD 100546. We model the spectrophotometric and multi-wavelength imaging observations using 2-Dust, a radiative transfer code, capable of producing spectral energy distributions (SEDs) and projected surface brightness maps. The SEDs and surface brightness maps are modeled using a passive disk in radiative and hydrostatic equilibrium, but with the addition of crystalline silicate forsterite grains, which are know to be present in the circumstellar dust composition of HD 100546 from spectroscopic observations. We compare the modeled SED to an observed SED constructed using spectra from the International Ultraviolet Explorer, the Infrared Space Observatory (ISO) Long-Wavelength and Short-Wavelength Spectrometer, photometric points from Infra-Red Astronomical Satellite (IRAS), and the literature. Likewise, we compare the modeled surface brightness images to near-IR ADONIS and NICMOS2 chronographic observations and ACS optical coronagraphic observations. We find that a layered passive disk used in some recent HD 1000546 SED models is not necessary to match its unusually large mid-IR excess.

This research was funded by NASA/NAG5-12595.