Precursors of UCHII regions & the evolution of massive outflows

Abstract

Since this contributions was meant to cover two subjects which are both in the field of massive star formation but which in its details can be discussed separately, this paper is divided in two sections. First, we present characteristics of precursors of UCH{\sc ii} regions and their likely evolutionary properties. The second section discusses massive molecular outflows, their implications for high-mass star formation, and a possible evolutionary sequence for massive outflows.Comment: 15 pages, 4 figures, in the Proceedings to the "Cores to Clusters" meeting held in Porto/Portigal in October 2004. Also available at http://cfa-www.harvard.edu/~hbeuther