EDP Sciences
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Volume 378, Number 1, October IV 2001
Page(s) 102 - 112
Section Formation, structure and evolution of stars
DOI http://dx.doi.org/10.1051/0004-6361:20011084

A&A 378, 102-112 (2001)
DOI: 10.1051/0004-6361:20011084

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

D. P. Kjurkchieva1, D. V. Marchev1 and W. Ogloza2

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

(Received 13 June 2001 / Accepted 23 July 2001 )

Spectroscopic observations in the range 6500-6700 Åand BVRI photometry of the eclipsing short-period RS CVn-star RT And are presented. We determined K1=130 km s-1 and K2=175.8 km s-1 by measurement of the double profiles of the lines H${\alpha}$ and FeI 6678, and obtained the mass ratio q=0.74 and masses of the star components M1=1.23 $M_{\odot}$ and M2=0.91 $M_{\odot}$. 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 H${\alpha}$. 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.

Key words: stars: activity -- binaries: eclipsing -- binaries: spectroscopic -- stars: chromospheres -- stars: individual: RT And -- stars: starspots

Offprint request: Waldemar Ogloza, ogloza@ap.krakow.pl

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© ESO 2001