Observations of eclipses of UU Sge

Abstract

We have performed spectroscopy and photometry of eclipses of the pre-cataclysmic variable UUSge using the 6-m telescope of the Special AstrophysicalObservatory and the 1. 5-mRussian-Turkish telescope. Our analysis of variations of the B-V and V-R color indices during the eclipses indicates that the temperature of the secondary is T eff,2 = 6000-6300 K. A similar value, T eff,2 = 6200 ± 200 K, follows from our comparison of the observed spectrum of UU Sge at the total eclipse phase and theoretical spectra of late-type stars. We identify 27 absorption lines of 11 chemical elements in the secondary's spectrum. Their abnormal intensities indicate possible high-velocity turbulent motions (up to ξ turb = 10. 0 km/s) in the atmosphere of the star and the presence of hot gas above its surface. © 2012 Pleiades Publishing, Ltd.