Published online by Cambridge University Press: 12 April 2016
We use a phenomenological approach to derive new constraints on the mass loss mechanisms working in the classical Be and the Herbig Ae/Be stars, which represent two groups of stars located very nearby in the HR diagram. We discuss observational similarities of classical Be and Herbig Be stars on one side, and stress, on the other side, the major differences between Herbig Ae and Herbig Be stars. For further details and a detailed bibliography, see Balona & Böhm (2000). A more quantitative approach will be needed and is deferred to future work.