Time-resolved spectroscopy of RS Canum Venaticorum short-period systems. II. RT Andromedae, WY Cancri, and XY Ursae Majoris

We present the second part of the results of our spectroscopic study of orb ital phase resolution of short-period active binaries. In this paper we pre sent the observations of the binaries RT And, WY Cnc, and XY UMa, for which we obtained simultaneous low-resolution spectra in the H alpha, H beta, an d Ca II infrared triplet (IRT; 8498 and 8542 Angstrom) lines, and higher re solution spectra in H alpha for WY Cnc and XY UMa. H alpha and H beta emiss ion excess was found in all the observed orbital phases of WY Cnc and XY UM a, while RT And showed Ha emission only during some orbital phases. We meas ure a clear Ca II (IRT) excess in all the spectra of the three binaries. Th e ratio of the flux excesses derived for these binaries, E-H alpha/E-H beta similar or equal to 1-3 and E-8542/E-8498 similar or equal to 1-3, give lo w values typical of solar plage structures. In the higher resolution H alph a spectra, we found emissions that can be associated with both stellar comp onents of XY UMa and WY Cnc, indicating that the faint secondary stars in b oth binaries are active late-type dwarfs. Some H alpha emission components, which could originate in extended structures between the stars, were detec ted in both systems.