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

Journal article, 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.