Spectroscopic and photometric observations of the short-period RS CVn star RT And

¹ Department of Physics, Shoumen University, 9700 Shoumen, Bulgaria and Isaac Newton Institute of Chile, Bulgarian Branch e-mail: d.kyurkchieva@shu-bg.net, d.marchev@shu-bg.net (Research supported in part by grants from Foundation Queen Jadwiga of the Jagiellonian University, Cracow, Poland.)
² Mt. Suhora Observatory, Cracow Pedagogical University, 30-084 Cracow and N. Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland

Corresponding author: Waldemar Ogloza, ogloza@ap.krakow.pl

Received: 13 June 2001
Accepted: 23 July 2001

Abstract

Spectroscopic observations in the range 6500-6700 Å and BVRI photometry of the eclipsing short-period RS CVn-star RT And are presented. We determined km s^-1 and km s^-1 by measurement of the double profiles of the lines Hα and FeI 6678, and obtained the mass ratio and masses of the star components and . It was established that the emission activity of RT And is associated with its secondary component. The relative contribution of the secondary star is stronger in the FeI 6678 line than in Hα. A strong emission feature between the two profiles of FeI 6678 at phase 0.73 was detected that is probably due to the appearance of extended emitting structure. The multicolor light curve of RT And is fitted by two cool spots on the primary star with equal sizes 21° and temperatures 4980 K and located at middle latitudes and longitudes symmetrical to the line connecting the star centers. Both spectral and photometric data lead to the conclusion that the secondary star of RT And is oversized for its mass.