Abstract
We presented evidences of accretion of matter in a sample of Herbig Ae/Be stars and we determined whether these events originated in a remnant gaseous structure from the primordial cloud (rich in Hydrogen) or in a metal rich body (like comets in our Solar System). During such analysis we also determined precise stellar parameters for this sample of stars. The stars were observed using high resolution spectroscopy (R = 48,000). A synthetic photospheric spectrum was constructed and then subtracted from the observed one in order to obtain the circumstellar component. An iterative procedure was applied in order to find the stellar parameters that were used to build the synthetic photospheric spectrum. Evidences of accretion were found for three stars: HD100546, HD142666 and HD145718. A chemical analysis of the accretion episodes suggest that the material is Hydrogen rich, what excludes the possibility that the accretion events were created by comet-like bodies.
