Precursors of complex organic molecules: NH₃ and CH₃OH in the ices surrounding low-mass protostars

Abstract

NH₃ and CH₃OH are key molecules in the chemical networks leading to the formation of complex N- and O-bearing organic molecules. However, despite a number of recent studies, there is still a lot to learn about their abundances in the solid state and how they relate to those of other N/O-bearing organic molecules or to NH₃ and CH₃OH abundances in the gas phase. This is particularly true in the case of low-mass young stellar objects (YSOs), for which only the recent advent of the Spitzer Space Telescope has allowed high sensitivity observations of the ices in their enveloppes. We present a combined study of Spitzer data (obtained within the Legacy program “From Molecular Cores to Planet-Forming Disks”, c2d) and laboratory spectra, leading to the detections of NH₃ and CH₃OH in the ices of low-mass protostars. We investigate correlations with other ice features and conclude with prospects on further studies linking these two precursors of complex organic molecules with their gas-phase products.