A SINGULAR INTERACTING ECLIPSING BINARY IN THE GALACTIC HALO

The IRAS source 00016 - 3056 is identified with a 508-d eclipsing binary situated in the halo, approximately 5 kpc above the Galactic plane. Near-infrared photometry, optical photometry and spectroscopy of the system are discussed. The JHK light curves show two eclipses as well as a pronounced reflection effect exceeding 0.5 mag at J. The primary is an early-M giant, possibly an AGB star, seen in the infrared through A(V) approximately 5.3 mag of extinction. In contrast, the optical light experiences much lower extinction (A(V) approximately 0.8 mag), and can be understood as the result of a reflection of one of the central stars from a circum-binary cloud. The nature of the secondary remains unclear, although various possibilities are discussed. It is suggested that the system may be a unique representative of a short-lived evolutionary phase and that changes due to evolution may be observable over a relatively short time interval.