Measured the amount of plasma between 10000 and 30 million degrees—responsible for the emission of extreme UV radiation and soft X-rays—in a sample of Sun-like and low-mass stars. Sun-like stars (spectral classes FGK) and low-mass stars (spectral class M) host in their outer atmospheres (the corona) plasma at temperatures of millions of degrees. Such high temperatures are reached through
Several astronomical studies rely on the precise determination of the chemical abundances of stars. For instance, the determination of chemical abundances of stars in different sites of the Milky Way, or with different age or evolutionary phase, can provide precious information on the evolution of our Galaxy. However, recently it has been discovered that spectroscopic determination of stellar chemical abundances
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
The study of the chemical abundances of stars with different age and position in the Milky Way provide crucial information on the formation and evolution of our Galaxy. In particular, heavy elements (i.e. those with the atomic number Z > 30) are produced by the successive capture of neutrons by lighter elements. This occurs by two processes, the slow s-process
Observing how the light emitted by stars changes with the time can be an interesting hobby, but it can also be something more important: an important and powerful diagnostic for something that can be hardly studied with some other approach… This can be particularly important for pre-main sequence stars with protoplanetary disks. In these stars, in fact, important and
