Despite the efforts made in recent years to understand the formation process of high-mass stars (M > 8-10 M⊙), fundamental questions remain. One concerns the timescales of different evolutionary phases, difficult to constrain because massive star progenitors remain embedded within their parental clumps throughout most of their formation. Nevertheless, the chemical composition of the clump is strongly influenced by the changes in density and temperature occurring during star formation. Specific chemical species can therefore be used as powerful chemical clocks to probe the evolutionary stage of the process.
Alessandro Ignesti
