Interferometry of $\epsilon$ Aurigae: Characterization of the asymmetric eclipsing disk

TL;DR

This study uses 14 years of optical interferometry to image and model the asymmetric eclipsing disk in the epsilon Aurigae system, revealing its structure and orbital parameters.

Contribution

It provides the first model-independent images of the disk during eclipse and derives new orbital elements using advanced 3D time-dependent modeling.

Findings

Confirmed the disk-like structure causes the eclipse

Derived new orbital parameters ($$, $i$)

Identified features like mid-eclipse brightening and potential disk warps

Abstract

We report on a total of 106 nights of optical interferometric observations of the $\epsilon$ Aurigae system taken during the last 14 years by four beam combiners at three different interferometric facilities. This long sequence of data provides an ideal assessment of the system prior to, during, and after the recent 2009-2011 eclipse. We have reconstructed model-independent images from the 10 in-eclipse epochs which show that a disk-like object is indeed responsible for the eclipse. Using new 3D, time-dependent modeling software, we derive the properties of the F-star (diameter, limb darkening), determine previously unknown orbital elements ($\Omega$, $i$), and access the global structures of the optically thick portion of the eclipsing disk using both geometric models and approximations of astrophysically relevant density distributions. These models may be useful in future hydrodynamical modeling of the system. Lastly, we address several outstanding research questions including mid-eclipse brightening, possible shrinking of the F-type primary, and any warps or sub-features within the disk.