Clustering around Herbig AeBe stars

We show that the observed correlation between the luminosity of young stars and the richness of associated clusters does not necessarily imply that there is a physical mechanism that favours the formation of massive stars in clusters. Instead, the data are compatible with a scenario in which stars are assembled at random into clusters with a spectrum of membership number, N. We also show that the required spectrum is of the form g(N)∝N−α, where α is in the range 1.5 to 2, and note that this is also the mass spectrum of clumps in molecular gas.