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HD179949 is an F8V star, orbited by a close-in giant planet with a period of~3 days. Previous studies suggested that the planet enhances the magneticactivity of the parent star, producing a chromospheric hot spot which rotatesin phase with the planet orbit. However, this phenomenon is intermittent sinceit was observed in several but not all seasons. A long-term monitoring of themagnetic activity of HD179949 is required to study the amplitude and timescales of star-planet interactions. In 2009 we performed a simultaneous opticaland X-ray spectroscopic campaign to monitor the magnetic activity of HD179949during ~5 orbital periods and ~2 stellar rotations. We analyzed the CaII H&Klines as a proxy for chromospheric activity, and we studied the X-ray emissionin search of flux modulations and to determine basic properties of the coronalplasma. A detailed analysis of the flux in the cores of the CaII H&K lines anda similar study of the X-ray photometry shows evidence of source variability,including one flare. The analysis of the the time series of chromospheric dataindicates a modulation with a ~11 days period, compatible with the stellarrotation period at high latitudes. Instead, the X-ray light curve suggests asignal with a period of ~4 days, consistent with the presence of two activeregions on opposite hemispheres. The observed variability can be explained,most likely, as due to rotational modulation and to intrinsic evolution ofchromospheric and coronal activity. There is no clear signature related to theorbital motion of the planet, but the possibility that just a fraction of thechromospheric and coronal variability is modulated with the orbital period ofthe planet, or the stellar-planet beat period, cannot be excluded. We concludethat any effect due to the presence of the planet is difficult to disentangle.

A coordinated optical and X-ray spectroscopic campaign on HD179949: searching for planet-induced chromospheric and coronal activity