The Prebiotic Molecular Inventory Of Serpens SMM1: II. The Building Blocks Of Peptide Chains

By Keith Cowing
February 21, 2022
Filed under
The Prebiotic Molecular Inventory Of Serpens SMM1: II. The Building Blocks Of Peptide Chains
Moment 0 maps of lines of NH2CHO, ν12=1, NH2CDO, CH3C(O)NH2, and CH3NHCHO toward SMM1. All lines are integrated over eight velocity bins, centred on the peak frequency of each line as determined toward SMM1-a. Positions of protostars in the SMM1 region are indicated and the beam size (1.3200×1.0400) is visualised in the bottom left corner. Dust continuum contours are given by the black dotted line at the levels of 0.02, 0.05, 0.1, 0.2, and 0.5 Jy Beam−1

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, NH132CHO, 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.

Niels F.W. Ligterink, Aida Ahmadi, Bijaya. Luitel, Audrey Coutens, Hannah Calcutt, Łukasz Tychoniec, Harold Linnartz, Jes K. Jørgensen, Robin T. Garrod, Jordy Bouwman

Comments: Accepted for publication in ACS Earth and Space Chemistry; 59 pages, 10 figures
Subjects: Astrophysics of Galaxies (astro-ph.GA); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2202.09640 [astro-ph.GA] or arXiv:2202.09640v1 [astro-ph.GA] for this version)
Submission history
From: Niels Ligterink
[v1] Sat, 19 Feb 2022 16:56:21 UTC (1,252 KB)
Astrobiology, Astrochemistry,

SpaceRef co-founder, Explorers Club Fellow, ex-NASA, Away Teams, Journalist, Space & Astrobiology, Lapsed climber.