A high-resolution study of complex organic molecules in hot cores

Artikel i vetenskaplig tidskrift, 2014

We present the results ofa line identification analysis using data from theIRAMPlateau de Bure Plateau de Bure Interferometer, focusing on six massive star-forming hot cores: G31.41+0.31, tify several transitions of vibrationally excited methyl formate (HCOOCH3) for the first time G29.96−0.02, G19.61−0.23, G10.62−0.38, G24.78+0.08A1 and G24.78+0.08A2.We iden- in these objects as well as transitions of other complex molecules, including ethyl cyanide (C2H5CN), and isocyanic acid (HNCO). We also postulate a detection of one transition of glycolaldehyde (CH2(OH)CHO) in two new hot cores. We find G29.96−0.02, G19.61−0.23, is chemically different: it manifests a larger chemical inventory and has significantly larger col- G24.78+0.08A1 and G24.78+0.08A2 to be chemically very similar. G31.41+0.31, however, umn densities. We suggest that it may represent a different evolutionary stage to the other hot cores in the sample, or it may surround a star with a higher mass. We derive column densities for methyl formate in G31.41+0.31, using the rotation diagram method, of 4 × 1017 cm−2 and methyl formate and methyl cyanide, all seem to trace the same material and peak at roughly a Trot of ∼170 K. For G29.96−0.02, G24.78+0.08A1 and G24.78+0.08A2, glycolaldehyde, the same position towards the dust emission peak. For G31.41+0.31, however, glycolaldehyde shows a different distribution to methyl formate and methyl cyanide and seems to trace the densest, most compact inner part of hot cores.