L. Testi (1,2), P. Palla (2), A. Natta (2)
(1) Division of Physics, Mathematics and Astronomy, Caltech, MS 105-24, Pasadena, CA 91125, USA
(2) Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy
No correlation of the richness of the stellar groups detected is found with the galactic position or the age of the central Herbig Ae/Be star.
The stellar volume densities estimated for the groups surrounding pre-main-sequence stars of intermediate mass show the transition from the low density aggregates of T Tauri stars and the dense clusters around massive stars.
Only the most massive stars (10-20Msun) are found to be associated with dense (10^3 pc^-3) stellar clusters. This is exactly the mass regime at which the conventional accretion scenario for isolated star formation faces theoretical problems. Thus our findings strongly supports the idea that the formation of high-mass stars is influenced by dynamical interaction in a young cluster environment.