Vol. 558
In section 6. Interstellar and circumstellar matter

Fragmentation, infall, and outflow around the showcase massive protostar NGC 7538 IRS1 at 500 AU resolution

by H. Beuther, H. Linz, and Th. Henning, A&A 558, A81


Systems such as the Trapezium stars are evidence that high-mass stars generally form as part of multiple systems. One would hope to be able to observe this multiplicity in the protostellar phase of the formation of a "Trapezium like system". This requires high angular resolution and it is encouraging that the study of Beuther et al. shows evidence that the inner core of NGC 7538 IRS1 at a distance of 2.7 kpc when observed with a resolution of 0.2 arc seconds splits into 3 substructures within the inner 3000 AU. There is also evidence of rapid infall onto these structures at a rate above 10^-3 solar masses per year. This observation presumably gives a hint of the potential of ALMA to uncover the secrets of high-mass star formation.