Universität zu Köln

Ordu, Matthias H., Zingsheim, Oliver, Belloche, Arnaud ORCID: 0000-0003-0046-6217, Lewen, Frank, Garrod, Robin T., Menten, Karl M., Schlemmer, Stephan ORCID: 0000-0002-1421-7281 and Mueller, Holger S. P. (2019). Laboratory rotational spectroscopy of isotopic acetone, (CH3C)-C-13(O)CH3 and (CH3C)-C-13(O)CH3, and astronomical search in Sagittarius B2(N2). Astron. Astrophys., 629. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 1432-0746

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Abstract

Context. Spectral lines of minor isotopic species of molecules that are abundant in space may also be detectable. Their respective isotopic ratios may provide clues about the formation of these molecules. Emission lines of acetone in the hot molecular core Sagittarius B2(N2) are strong enough to warrant a search for its singly substituted C-13 isotopologs. Aims. We want to study the rotational spectra of (CH3C)-C-13(O)CH3 and (CH3C)-C-13(O)CH3 and search for them in Sagittarius B2(N2). Methods. We investigated the laboratory rotational spectrum of isotopically enriched (CH3C)-C-13(O)CH3 between 40 GHz and 910 GHz and of acetone between 36 GHz and 910 GHz in order to study (CH3C)-C-13(O)CH3 in natural isotopic composition. In addition, we searched for emission lines produced by these species in a molecular line survey of Sagittarius B2(N) carried out with the Atacama Large Millimeter/submillimeter Array (ALMA). Discrepancies between predictions of the main isotopic species and the ALMA spectrum prompted us to revisit the rotational spectrum of this isotopolog. Results. We assigned 9711 new transitions of (CH3C)-C-13(O)CH3 and 63 new transitions of (CH3C)-C-13(O)CH3 in the laboratory spectra. More than 1000 additional transitions were assigned for the main isotopic species. We modeled the ground state data of all three isotopologs satisfactorily with the ERHAM program. We find that models of the torsionally excited states v(12) = 1 and v(17) = 1 of CH3C(O)CH3 improve only marginally. No transitrrrion of (CH3C)-C-13(O)CH3 is clearly detected toward the hot molecular core Sgr B2(N2). However, we report a tentative detection of (CH3C)-C-13(O)CH3 with a C-12/C-13 isotopic ratio of 27 that is consistent with the ratio previously measured for alcohols in this source. Several dozens of transitions of both torsional states of the main isotopolog are detected as well. Conclusion. Our predictions of (CH3C)-C-13(O)CH3 and CH3C(O)CH3 are reliable into the terahertz region. The spectrum of (CH3C)-C-13(O)CH3 should be revisited in the laboratory with an enriched sample. The torsionally excited states v(12) = 1 and v(17) = 1 of CH3C(O)CH3 were not reproduced satisfactorily in our models. Nevertheless, transitions pertaining to both states could be identified unambiguously in Sagittarius B2(N2).

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ordu, Matthias H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zingsheim, Oliver UNSPECIFIED UNSPECIFIED UNSPECIFIED Belloche, Arnaud UNSPECIFIED orcid.org/0000-0003-0046-6217 UNSPECIFIED Lewen, Frank UNSPECIFIED UNSPECIFIED UNSPECIFIED Garrod, Robin T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menten, Karl M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schlemmer, Stephan UNSPECIFIED orcid.org/0000-0002-1421-7281 UNSPECIFIED Mueller, Holger S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-141658
DOI:	10.1051/0004-6361/201935887
Journal or Publication Title:	Astron. Astrophys.
Volume:	629
Date:	2019
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	1432-0746
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Physics > Institute of Physics I
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INTERNAL ROTORS; SPECTRUM; SUBMILLIMETER; MILLIMETER; MOLECULES; MICROWAVE; CYANIDE; CH3COCH3; FORMATE Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/14165