DR Tau: Temporal variability of the brightness distribution in the potential planet-forming region

TL;DR

This study examines the temporal changes in the brightness distribution of DR Tau's protoplanetary disk over nine years using MIR interferometry, revealing structural variations that influence disk modeling.

Contribution

It demonstrates that the disk structure of DR Tau varies over time and can be modeled with a consistent density distribution by adjusting parameters like scale height.

Findings

Disk structure varies over nine years.

A single disk model can fit multiple epochs with parameter adjustments.

Brightness distribution changes are linked to disk density and height.

Abstract

We investigate the variability of the brightness distribution and the changing density structure of the protoplanetary disk around DR Tau, a classical T Tauri star. DR Tau is known for its peculiar variations from the ultraviolet (UV) to the mid-infrared (MIR). Our goal is to constrain the temporal variation of the disk structure based on photometric and MIR interferometric data. We observed DR Tau with the MID-infrared Interferometric instrument (MIDI) at the Very Large Telescope Interferometer (VLTI) at three epochs separated by about nine years, two months, respectively. We fit the spectral energy distribution and the MIR visibilities with radiative transfer simulations. We are able to reproduce the spectral energy distribution as well as the MIR visibility for one of the three epochs (third epoch) with a basic disk model. We were able to reproduce the very different visibility curve obtained nine years earlier with a very similar baseline (first epoch), using the same disk model with a smaller scale height. The same density distribution also reproduces the observation made with a higher spatial resolution in the second epoch, i.e. only two months before the third epoch.