Multiwavelength interferometric observations and modeling of circumstellar disks

TL;DR

This study uses multiwavelength interferometry and 3D radiative transfer modeling to analyze the inner structures of circumstellar disks around young stars, identifying a disk gap in HD 142666 but not in AS 205.

Contribution

It provides the first spatially resolved infrared observations of these disks and demonstrates the effectiveness of combined interferometry and modeling to detect disk gaps.

Findings

Disk gap found in HD 142666 at 0.30AU radius.

No evidence of gaps in AS 205, confirming its classification.

Interferometric data consistent with 3D radiative transfer models.

Abstract

We investigate the structure of the innermost region of three circumstellar disks around pre-main sequence stars HD 142666, AS 205 N, and AS 205 S. We determine the inner radii of the dust disks and, in particular, search for transition objects where dust has been depleted and inner disk gaps have formed at radii of a few tenths of AU up to several AU. We performed interferometric observations with IOTA, AMBER, and MIDI in the infrared wavelength ranges 1.6-2.5um and 8-13um with projected baseline lengths between 25m and 102m. The data analysis was based on radiative transfer simulations in 3D models of young stellar objects (YSOs) to reproduce the spectral energy distribution and the interferometric visibilities simultaneously. Accretion effects and disk gaps could be considered in the modeling approach. Results from previous studies restricted the parameter space. The objects of this study were spatially resolved in the infrared wavelength range using the interferometers. Based on these observations, a disk gap could be found for the source HD 142666 that classifies it as transition object. There is a disk hole up to a radius of R_in=0.30AU and a (dust-free) ring between 0.35AU and 0.80AU in the disk of HD 142666. The classification of AS 205 as a system of classical T Tauri stars could be confirmed using the canonical model approach, i. e., there are no hints of disk gaps in our observations.