Laboratory Rotational Spectroscopy Leads to the First Interstellar Detection of Singly Deuterated Methyl Mercaptan (CH<sub>2</sub>DSH)
Abstract We report an extensive rotational spectroscopic analysis of singly deuterated methyl mercaptan (CH 2 DSH) using both millimeter and far-infrared synchrotron spectra to achieve a global torsional analysis of the three lowest torsional substates ( e 0 , e 1 , and o 1 ) of this nonrigid species. A fit including 3419 millimeter-wave transitions along with 43 infrared torsional subband centers was performed with rms deviations of 0.233 MHz and 0.270 cm −1 , respectively, resulting in 68 fit parameters. A spectroscopic catalog built from this analysis for a temperature of 125 K has led to the first interstellar detection of CH 2 DSH toward the solar-like protostar IRAS 16293-2422 B. We report the identification of 46 transitions, including eight relatively unblended lines, resulting in a derived column density of (3.0 ± 0.3) × 10 14 cm −2 . The column density ratio for HDCS/CH 2 DSH compared to HDCO/CH 2 DOH suggests a difference in the interstellar chemistry between the sulfur and oxygen complex organics, in particular a different link between H 2 CO and CH 3 OH and between H 2 CS and CH 3 SH. This is the first interstellar detection of a deuterated sulfur-bearing complex organic molecule and therefore an important step toward understanding the chemical origin of sulfur-based prebiotics.
Authors
- S. Spezzano (ORCID: https://orcid.org/0000-0002-6787-5245)
- L. H. Coudert (ORCID: https://orcid.org/0000-0003-0498-6957)
- Hayley Bunn (ORCID: https://orcid.org/0000-0002-7783-3049)
- Christian Endres (ORCID: https://orcid.org/0000-0002-7104-8795)
- Olivier Pirali (ORCID: https://orcid.org/0000-0002-4332-1440)
- Valerio Lattanzi (ORCID: https://orcid.org/0000-0001-9819-1658)
- Jean‐Claude Guillemin (ORCID: https://orcid.org/0000-0002-2929-057X)
- Yuxin Lin (ORCID: https://orcid.org/0000-0001-9299-5479)
- Brant Billinghurst (ORCID: https://orcid.org/0000-0002-5346-5317)
- P. Caselli (ORCID: https://orcid.org/0000-0003-1481-7911)
- Jes Kristian Jørgensen (ORCID: https://orcid.org/0000-0001-9133-8047)
Institutions
- University of Copenhagen (DK)
- Centre National de la Recherche Scientifique (FR)
- Université Paris-Saclay (FR)
- Synchrotron soleil (FR)
- University of Saskatchewan (CA)
- Institut des Sciences Chimiques de Rennes (FR)
- Max Planck Institute for Extraterrestrial Physics (DE)
- École Nationale Supérieure de Chimie de Rennes (FR)
- Institut des Sciences Moléculaires d'Orsay (FR)
- Université de Rennes (FR)
- Canadian Light Source (Canada) (CA)
Publication Details
- Journal
- The Astrophysical Journal Letters
- Published
- 2025-02-10
- DOI
- https://doi.org/10.3847/2041-8213/adacea
- Citations
- 3
- Primary Topic
- Molecular Spectroscopy and Structure
- Type
- article
- Field-Weighted Citation Impact
- 2.27
Funders
- Canadian Light Source
- Centre National d’Etudes Spatiales
- Max-Planck-Gesellschaft
- Centre National de la Recherche Scientifique
- Canadian Institutes of Health Research
- Natural Sciences and Engineering Research Council of Canada