Year: 2024
Type: article
Abstract: We have started a measurement campaign of numerous methanol isotopologs in low-lying torsional states in order to provide extensive line lists for radio astronomical observations from an adequate spectroscopic model and to investigate how the intricate vibrationtorsion-rotation interactions manifest themselves in the spectra of different isotopic species. After CD3OH and CD3OD, we turn our focus to CH3OD, which is an important species for studying deuteration in prestellar cores and envelopes that enshroud protostars. Notably, deuteration is frequently viewed as a diagnostic tool for star formation. The measurements used in this study were obtained in two spectroscopic laboratories and cover large fractions of the 34 GHz-1.35 THz range. As done in previous studies, we employed a torsion-rotation Hamiltonian model for our analysis that is based on the rho-axis method. The resulting model describes the ground and first excited torsional states of CH3OD well up to quantum numbers J ⩽ 51 and Ka ⩽ 18. We derived a line list for radio astronomical observations from this model that is accurate up to at least 1.35 THz and should be sufficient for all types of radio astronomical searches for this methanol isotopolog in these two lowest torsional states. This line list was applied to a reinvestigation of CH3OD in data from the Protostellar Interferometric Line Survey of IRAS 16293–2422 obtained with the Atacama Large Millimeter/submillimeter Array. The new accurately determined value for the column density of CH3OD implies that the deuteration in methanol differs in its two functional groups by a factor of ~7.5.
Source: Astronomy and Astrophysics
Institutions: Institute of Radio Astronomy, University of Cologne, Physikalisch-Meteorologisches Observatorium Davos, University of Copenhagen, Technische Universität Braunschweig, Centre National de la Recherche Scientifique, Université de Lille, Laboratoire de Physique des Lasers, Atomes et Molécules, University of New Brunswick
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,732
Funders: National Science Foundation, National Aeronautics and Space Administration, Gruber Foundation, National Radio Astronomy Observatory, Université de Lille, Deutsche Forschungsgemeinschaft, Volkswagen Foundation, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, Korea Astronomy and Space Science Institute, Centre National de la Recherche Scientifique, National Astronomical Observatory of Japan, Science and Technology Center in Ukraine, Holcim Stiftung zur Förderung der Wissenschaftlichen Fortbildung, Natural Sciences and Engineering Research Council of Canada, National Institutes of Natural Sciences
Awards: G2163688638, G4750678880, SFB 956: Bedingungen und Auswirkungen der Sternentstehung Astrophysik, Instrumentierung und Labor, G552708993, The planetary cookbook: chemical composition of volatiles and refractories from star-forming regions to comets and planetesimals, G7823692103, SFB 1601: Die kosmische Entwicklung der Lebensräume massereicher Sterne
OpenAlex ID: W4399480910