Star-spot distributions and chromospheric activity on the RS CVn type eclipsing binary SV Cam

TL;DR

This study maps surface spots and chromospheric activity on the primary star of the eclipsing binary SV Cam, revealing high-latitude spots, active secondary component, and dominant chromospheric plages linked to star-spots.

Contribution

First high-resolution surface maps of SV Cam's primary component showing high-latitude spots and detailed chromospheric activity analysis.

Findings

High-latitude spots at 60-70 degrees with 35% filling factor

Strong chromospheric activity on the secondary star

Presence of cool material obscuring the primary star

Abstract

Using a time series of high-resolution spectra and high-quality multi-colour photometry, we reconstruct surface maps of the primary component of the RS CVn type rapidly rotating eclipsing binary, SV Cam (F9V + K4V). We measure a mass ratio, q, of 0.641(2) using our highest quality spectra and obtain surface brightness maps of the primary component, which exhibit predominantly high-latitude spots located between 60-70-degree latitudes with a mean filling factor of about 35%. This is also indicated by the R-band light curve inversion, subjected to rigourous numerical tests. The spectral subtraction of the H-alpha line reveals strong activity of the secondary component. The excess H-alpha absorption detected near the secondary minimum hints to the presence of cool material partially obscuring the primary star. The flux ratios of Ca II IRT excess emission indicate that the contribution of chromospheric plage regions associated with star-spots is dominant, even during the passage of the filament-like absorption feature.