A star hosting six terrestrial-type planets and showing intense X-ray emission, with a cyclic behavior on a timescale of about two years, which may have a significant impact on the properties of the planets and their atmospheres. The magnetic activity of a star manifests itself through a variety of high-energy phenomena that produce X-ray and UV radiation. Studying this
The intensity of Solar magnetic activity and of the related phenomena (such as sunspots and flares) varies with an 11-years cycle. In order to understand whether such an activity cycle is common among solar-type stars, since 1966 a project based on the Observatory of Mt. Wilson is collecting measurements of the cromospheric activity of a large sample of low-mass stars
