2022/02/19 by Niels F. W. Ligterink, Ligterink, Niels F. W., Aida Ahmadi +17
Physics and Astronomy · #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Solar and Stellar Astrophysics (astro-ph.SR) #astro-ph.GA #astro-ph.SR
paper · pdf · doi:10.48550/arxiv.2202.09640
Accepted for publication in ACS Earth and Space Chemistry; 59 pages, 10 figures
arxiv created 2022/02/19 · arxiv updated 2022/02/22
This work aims to constrain the abundances of interstellar amides, by searching for this group of prebiotic molecules in the intermediate-mass protostar Serpens SMM1-a. ALMA observations are conducted toward Serpens SMM1. A spectrum is extracted toward the SMM1-a position and analyzed with the CASSIS line analysis software for the presence of characteristic rotational lines of a number of amides and other molecules. NH2CHO, NH2CHO ν12=1, NH213CHO, CH3C(O)NH2 ν=0,1, CH2DOH, CH3CHO, and CH3C(O)CH3 are securely detected, while trans-NHDCHO, NH2CDO, CH3NHCHO ν=0,1, CH3COOH, and HOCH2CHO are tentatively identified. The results of this work are compared with detections presented in the literature. A uniform CH3C(O)NH2/NH2CHO ratio is found for a group of interstellar sources with vast physical differences. A similar ratio is seen for CH3NHCHO, based on a smaller data sample. The D/H ratio of NH2CHO is about 1--3% and is close to values found in the low-mass source IRAS~16293--2422B. The formation of CH3C(O)NH2 and NH2CHO is likely linked. Formation of these molecules on grain surfaces during the dark cloud stage is a likely scenario. The high D/H ratio of NH2CHO is also seen as an indication that these molecules are formed on icy dust grains. As a direct consequence, amides are expected to be present in the most pristine material from which planetary systems form, thus providing a reservoir of prebiotic material.