The new pre-cataclysmic binary PG 2200+085

Abstract

We present the results of spectroscopic-- and orbit--sampled photometric observations of the faint UV-excess object PG 2200+085. The optical CCD photometry observations of this object were performed by the Russian-Turkish 1.5-meter telescope RTT150 at the TUBITAK National Observatory (Turkey). The long-slit optical spectroscopy observations with 2.6 A resolution were carried out by 6-meter telescope BTA at the Special Astrophysical Observatory (Russia). The photometric variations over two nights are almost sinusoidal with an amplitude Δm_V = 0.04 m and a period of P = 0.3186 d. Such a light curve is typical of a detached close binary with an illumination effect or the ellipsoidal deformation of a secondary star. The observed spectrum clearly displays a featureless blue continuum of a hot component and a rich absorption--line and molecular band K--star spectrum. The CaII line profiles with strong emission cores are remarkably similar to those of V471 Tau. We tentatively classify PG 2200+085 as a pre-cataclysmic binary of the V471 Tau type.