Chromospheric activity on the RS Canum Venaticorum binary SZ Piscium

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. Results. All indicators show that the chromospheric activity of the system is associated with the cooler component. We find that the values of EW 8542 /EW 8498 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 Ca ii 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 Na i D 1 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.

New observations of chromospheric and prominence activity on the RS CVn-type binary SZ Piscium

“…Secondly, the v sin i values were recalculated by fixing the values of the radial velocity and the intensity weight ratio. The v sin i values (3.4 & 76.9 km s −1 ) of the components of SZ Psc were obtained, which are slightly different from the values published by Zhang & Gu (2008) because different reference stars were used, which have differently intrinsic v sin i values. Finally, the synthesized H α spectra were constructed with the parameters calculated above.…”

“…The spectrum reduction was performed with the IRAF package, following the standard procedure described by Zhang & Gu (2008). In Table 1, we give the observing log, which includes the observing date, the heliocentric Julian date (HJD), orbital phase, exposure time, and the signal-to-noise ratio (S /N).…”

“…We initially set the v sin i values to 0 & 78 km s −1 (Zhang & Gu 2008) for the two components, and then determined the radial velocity and the intensity weight ratio using the method described in detail by Barden (1985) in the spectra spanning the wavelength region 6381-6789 Å (five echelle orders) except the H α line. We obtained the radial velocity by averaging the values of the five echelle orders, and adopted the averaging values (0.17/0.83) as the final intensity weight ratio for the H α spectral region.…”

“…It is interesting that Zhang & Gu (2008) detected some absorption features in the subtracted H α profiles of SZ Psc, which may be explained by three possible prominences. In view of this interesting finding, we aim to search for prominence-like events and carried out additional studies for this system in the present work, based on higher time-resolved spectroscopic observations of the H α line.…”

“…It shows strong chromospheric activity, as demonstrated by several optical active lines: Ca ii H & K, Mg i b, Na i D 1 , D 2 , H α , and Ca ii IRT (Jakate et al 1976;Bopp 1981;Huenemoerder & Ramsey 1984;Fernández-Figueroa et al 1986;Popper 1988;Doyle et al 1994;Frasca & Catalano 1994;Fernández-Figueroa et al 1994;Kang et al 2003;Eaton & Henry 2007;Zhang & Gu 2008).…”