The chemical composition of very young open clusters in the Solar neighbourhood

The spectroscopic analysis of very young stars is not starightforward. Increased levels of stellar activity alter the formation of spectral lines in the upper layers of the photosphere, Thus, the derivation of the stellar atmospheric parameters (in particular microturbulence velocity) and consequently the chemical abundances are dramatically affected. The magnetic activity could be the explanation behind the chemical peculiarities of very young open clusters in the solar vicinity, like the local anaemia or the Ba enhancements. The results of our work have drawn attention to the necessity to revise the spectroscopic analysis techniques applied to very young stars.