A Look Inside the Disk in the ∊ Aurigae Binary System

Interferometric imaging, combined with spectroscopy, is providing a powerful way to unlock the long-kept secrets of the engimatic eclipsing system, ∊ Aurigae, that has puzzled astronomers for many decades. A sequence of H-band MIRC images obtained at the CHARA Array during the 2010 eclipse, is augmented with spectra obtained by a worldwide network of observers participating in the eclipse campaign. The MIRC images confirm the hypothesized dark disk, revealing it to have dimensions of ∼8 AU long by ∼0.7 AU thick, that occults the southern hemisphere of the 135R_☉ F-star primary; however, these dimensions are dependent on the assumed distance, which still is not settled. Spectra reveal a wealth of changes caused by facets of the disk that can be associated with substructure, including possible rings, a central ionized region, and evidence for accretion onto a hot embedded object. Results reported here are due to the help of numerous observers to whom I am indebted, and support for this effort that was derived in part from a bequest of William Herschel Womble in support of astronomy at the University of Denver, from NSF grant 1016678, and from JPL RSA 1414715 to the University of Denver.