Mid-infrared observations of the transitional disks around DH Tauri, DM Tauri, and GM Aurigae

Abstract

\n Aims. We present mid-infrared observations and photometry of the transitional disks around the young stellar objects <ext-link ext-link-type="aoi">DH Tau</ext-link>, <ext-link ext-link-type="aoi">DM Tau</ext-link>, and <ext-link ext-link-type="aoi">GM Aur</ext-link>, obtained with VISIR/VLT in N band. Our aim is to resolve the inner region and the large-scale structures of these transitional disks, carrying potential signatures of intermediate or later stages of disk evolution and ongoing planet formation.\n Methods. We use the simultaneously observed standard-stars as PSF reference to constrain the radial flux profiles of our target objects. Subtracting the obtained standard-star profile from the corresponding science object profile yields the flux residuals produced by the star-disk system. A detection threshold takes into account the background standard deviation and also the seeing variations during the observations to evaluate the significance of these flux residuals. On the basis of a simple model for the dust re-emission, we derive constraints on the inner radius of the dust disk.\n Results. We spatially resolve the transitional disk around GM Aur and determine an inner-disk hole radius of \\hbox{$20.5^{+1.0}_{-0.5}$} AU. The circumstellar disks around DH Tau and DM Tau are not spatially resolved but we are able to constrain the inner-disk hole radius to &lt;\\hbox{$15.5^{+9.0}_{-2.0}$} AU and &lt;\\hbox{$15.5^{+0.5}_{-0.5}$} AU, respectively. The performed photometry yields fluxes of 178 ± 31 mJy for DH Tau, 56 ± 6 mJy for DM Tau, and 229 ± 14 mJy for GM Aur. \n