Universität zu Köln

Ligterink, N. F. W., Coutens, A., Kofman, V., Mueller, H. S. P., Garrod, R. T., Calcutt, H., Wampfler, S. F., Jorgensen, J. K., Linnartz, H. and van Dishoeck, E. F. (2017). The ALMA-PILS survey: detection of CH3NCO towards the low-mass protostar IRAS 16293-2422 and laboratory constraints on its formation. Mon. Not. Roy. Astron. Soc., 469 (2). S. 2219 - 2230. OXFORD: OXFORD UNIV PRESS. ISSN 1365-2966

Full text not available from this repository.

Abstract

Methyl isocyanate (CH3NCO) belongs to a select group of interstellar molecules considered to be relevant precursors in the formation of larger organic compounds, including those with peptide bonds. The molecule has only been detected in a couple of high-mass protostars and potentially on comets. A formation route on icy grains has been postulated for this molecule but experimental evidence is lacking. Here we extend the range of environments where methyl isocyanate is found and unambiguously identify CH3NCO through the detection of 43 unblended transitions in the ALMA Protostellar Interferometric Line Survey (PILS) of the low-mass solar-type protostellar binary IRAS 16293-2422. The molecule is detected towards both components of the binary with a ratio HNCO/CH3NCO similar to 4-12. The isomers CH3CNO and CH3OCN are not identified, resulting in upper abundance ratios of CH3NCO/CH3CNO > 100 and CH3NCO/CH3OCN > 10. The resulting abundance ratios compare well with those found for related N-containing species towards high-mass protostars. To constrain its formation, a set of cryogenic UHV experiments is performed. VUV irradiation of CH4:HNCO mixtures at 20 K strongly indicate that methyl isocyanate can be formed in the solid state through CH3 and (H)NCO recombinations. Combined with gas-grain models that include this reaction, the solid-state route is found to be a plausible scenario to explain the methyl isocyanate abundances found in IRAS 16293-2422.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Ligterink, N. F. W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Coutens, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kofman, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, H. S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Garrod, R. T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Calcutt, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wampfler, S. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jorgensen, J. K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Linnartz, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED van Dishoeck, E. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-224239
DOI:	10.1093/mnras/stx890
Journal or Publication Title:	Mon. Not. Roy. Astron. Soc.
Volume:	469
Number:	2
Page Range:	S. 2219 - 2230
Date:	2017
Publisher:	OXFORD UNIV PRESS
Place of Publication:	OXFORD
ISSN:	1365-2966
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language COMPLEX ORGANIC-MOLECULES; INTERSTELLAR ICE ANALOGS; SOLAR-TYPE PROTOSTAR; EXTRAORDINARY SOURCES ANALYSIS; SURVEY 1ST DETECTIONS; LINE SURVEY; HERSCHEL OBSERVATIONS; MICROWAVE-SPECTRUM; METHYL ISOCYANATE; SAGITTARIUS B2(N) Multiple languages Astronomy & Astrophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/22423