Chromospheric activity on the RS Canum Venaticorum binary SZ Piscium

¹ National Astronomical Observatories/Yunnan Observatory, Joint laboratory for Optical Astronomy, Chinese Academy of Sciences, Kunming 650011, PR China e-mail: liy_zhang@hotmail.com
² Graduate School of Chinese Academy of Sciences, Beijing 100039, PR China

Received: 29 February 2008
Accepted: 10 June 2008

Abstract

Aims. We present the new high-resolution echelle spectra of SZ Psc, obtained in Nov. 2004 and Sep.-Dec. 2006, and study its chromospheric activity.

Methods. By means of the spectral subtraction technique, we analyze our spectroscopic observations including several optical chromospheric activity indicators (the  D₃,  D₁, D₂, H_α, and  infrared triplet lines).

Results. All indicators show that the chromospheric activity of the system is associated with the cooler component. We find that the values of are in the range 1-3, which indicates optically thick emission in plage-like regions. The 2006 data suggest the presence of active longitude phenomena. For the  8542 and 8662 and the H_α lines, it seems that the excess emission is stronger near the two quadratures of system. This may be anti-correlated with the behavior of the  D₁ line. The absorption features are detected in the subtracted H_α lines, which could be explained by prominence-like extended material seen on the stellar disk or by mass transfer from the cooler component to the hotter one.