HD97048: a closer look to the disk

Abstract

Aims: Today, large ground-based instruments, like VISIR on the VLT, providing diffraction-limited (about 0.3 arcsec) images in the mid-infrared where strong PAH features appear enable us to see the flaring structure of the disks around Herbig Ae stars. Although great progress has been made in modelling the disk with radiative transfer models able to reproduce the spectral energy distribution (SED) of Herbig Ae stars, the constraints brought by images have not been yet fully exploited. Here, we are interested in checking if these new observational imaging constraints can be accounted for by predictions based on existing models of passive centrally irradiated hydrostatic disks made to fit the SEDs of the Herbig Ae stars. Methods: The images taken by VISIR in the 8.6 and 11.3 microns aromatic features reveal a large flaring disk around HD97048 inclined to the line of sight. In order to analyse the spatial distribution of these data, we use a disk model which includes the most up to date understanding of disk structure and physics around Herbig Ae stars with grains in thermal equilibrium in addition to transiently-heated PAHs. Results: We compare the observed spatial distribution of the PAH emission feature and the adjacent continuum emission with predictions based on existing full disk models. Both SED and spatial distribution are in very good agreement with the model predictions for common disk parameters. Conclusions: We take the general agreement between observations and predictions as a strong support for the physical pictures underlying our flared disk model.