A BeppoSAX observation of HD 9770: a visual triple system containing a recently discovered short-period eclipsing binary

We have studied the coronal X-ray emission of the recently discovered short -period eclipsing binary HD 9770 with the BeppoSAX satellite. The data from the Low Energy and Medium Energy Concentrator Spectrometers (LECS & MECS) onboard BeppoSAX allow studying the spectrum of this star from 0.1 to 8 keV , confirming that this is a very active coronal source, with strong flaring activity. The X-ray emission most likely originates from the eclipsing bin ary itself, rather than from the other visual component of the system. The Xray light curves could be modulated with the orbital period of the eclipsi ng binary, with a hint for a different orbital modulation of the cooler and hotter plasma. The X-ray spectrum is characterized by hot plasma, with the Fe K complex at 6.7 keV clearly detected in the MECS spectrum, and it is w ell fitted by a 2-temperature optically thin plasma model with low metal ab undances (similar to 0.3 Z.). These results are in line with those found fo r many other active stars. As expected, during the flare the Xray emission is dominated by hotter plasma with a temperature > 4 keV. There is an indic ation that the metal abundance may be somewhat higher during the flare.