Speaker: Laure Bouscasse (chair: Davit Alkhanishvili)
Title: Chemical differentiation in high-mass protostellar objects
The physical conditions in massive dense cores (MDCs) leading to high-mass star formation are poorly constrained. Observations are lacking to confront theory. From the 870 micron ATLASGAL survey of the inner Galaxy, in the frame of the SPARKS project (Survey for high-mass Protostars with ALMA Revealed up to Kpc Scales, PI: Csengeri), we performed an ALMA follow-up on the most massive mid-infrared quiet clumps within 5 kpc. We found 6 sources that stay single from 0.3 pc to 2000 au scales. This makes them relatively easy targets for single-dish observations to study the early warm-up phase chemistry leading to the appearance of classical hot-cores. In addition to the 8 GHz instantaneous bandwidth at 345GHz obtained with SPARKS, we obtained a complete spectral survey covering the 2 mm, 1 mm and 0.8 mm atmospheric window with the APEX telescope towards a handful of sources. We will present here the chemical composition of the protostellar envelopes and pin down where different molecules are located within the envelope with a particular focus on the distribution and diversity of complex organic molecules.