The physical and chemical structure of high-mass star-forming regions: Unraveling chemical complexity with the NOEMA large program CORE
Caroline Gieser
Tuesday December 1st, 15:15
Characterizing the physical and chemical properties of forming massive stars at the spatial resolution of individual high-mass cores lies at the heart of current star formation research. We use sub-arcsecond resolution (∼0.4") observations with the NOrthern Extended Millimeter Array (NOEMA) at 1.37 mm to study the dust emission and molecular gas of 18 high-mass star-forming regions. We combine the derived physical and chemical properties of individual cores in these regions to estimate their ages. Within the 18 observed regions, 22 individual cores can be identified with associated 1.37 mm continuum emission and with a radially decreasing temperature profile. We find an average temperature power-law index of q = 0.4 ± 0.1 and an average density power-law index of p = 2.0 ± 0.2 on scales on the order of several 1 000 au. Comparing these results with values of p derived in the literature suggest that the density profiles remain unchanged from clump to core scales. We apply the physical-chemical model MUlti Stage ChemicaL codE (MUSCLE) to the derived column densities of each core and find a mean chemical age of ∼60 000 yrs and an age spread of 20 000 − 100 000 yrs. The CORE sample reveals well constrained density and temperature power-law distributions. Furthermore, we characterize a large variety in molecular richness that can be explained by an age spread confirmed by our physical-chemical modeling. The hot molecular cores show the most emission lines, but we also find evolved cores at an evolutionary stage, in which most molecules are destroyed and thus the spectra appear line-poor again.