Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F22%3A43923999" target="_blank" >RIV/60461373:22340/22:43923999 - isvavai.cz</a>

Result on the web

<a href="https://www.aanda.org/articles/aa/full_html/2022/10/aa43627-22/aa43627-22.html" target="_blank" >https://www.aanda.org/articles/aa/full_html/2022/10/aa43627-22/aa43627-22.html</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202243627" target="_blank" >10.1051/0004-6361/202243627</a>

Result language

angličtina

Original language name

Millimeter wave spectrum and search for vinyl isocyanate toward Sgr B2(N) with ALMA

Original language description

Context. The interstellar detections of isocyanic acid (HNCO), methyl isocyanate (CH3NCO), and very recently also ethyl isocyanate (C2H5NCO) invite the question of whether or not vinyl isocyanate (C2H3NCO) can be detected in the interstellar medium. There are only low-frequency spectroscopic data (&lt;40 GHz) available for this species in the literature, which makes predictions at higher frequencies rather uncertain, which in turn hampers searches for this molecule in space using millimeter (mm) wave astronomy.Aims. The aim of the present study is on one hand to extend the laboratory rotational spectrum of vinyl isocyanate to the mm wave region and on the other to search, for the first time, for its presence in the high-mass star-forming region Sgr B2, where other isocyanates and a plethora of complex organic molecules are observed.Methods. We recorded the pure rotational spectrum of vinyl isocyanate in the frequency regions 127.5–218 and 285–330 GHz using the Prague mm wave spectrometer. The spectral analysis was supported by high-level quantum-chemical calculations. On the astronomy side, we assumed local thermodynamic equilibrium to compute synthetic spectra of vinyl isocyanate and to search for it in the ReMoCA survey performed with the Atacama Large Millimeter/submillimeter Array (ALMA) toward the high-mass star-forming protocluster Sgr B2(N). Additionally, we searched for the related molecule ethyl isocyanate in the same source.Results. Accurate values for the rotational and centrifugal distortion constants are reported for the ground vibrational states of trans and cis vinyl isocyanate from the analysis of more than 1000 transitions. We report nondetections of vinyl and ethyl isocyanate toward the main hot core of Sgr B2(N). We find that vinyl and ethyl isocyanate are at least 11 and 3 times less abundant than methyl isocyanate in this source, respectively.Conclusions. Although the precise formation mechanism of interstellar methyl isocyanate itself remains uncertain, we infer from existing astrochemical models that our observational upper limit for the CH3NCO:C2H5NCO ratio in Sgr B2(N) is consistent with ethyl isocyanate being formed on dust grains via the abstraction or photodissociation of an H atom from methyl isocyanate, followed by the addition of a methyl radical. The dominance of such a process for ethyl isocyanate production, combined with the absence of an analogous mechanism for vinyl isocyanate, would indicate that the ratio C2H3NCO:C2H5NCO should be less than unity. Even though vinyl isocyanate was not detected toward Sgr B2(N), the results of this work represent a significant improvement on previous low-frequency studies and will help the astronomical community to continue searching for this species in the Universe.

Czech name

—

Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10403 - Physical chemistry

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2022

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

ASTRONOMY &amp; ASTROPHYSICS

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

666

Issue of the periodical within the volume

October 2022

Country of publishing house

FR - FRANCE

Number of pages

16

Pages from-to

"A50"

UT code for WoS article

000863750000002

EID of the result in the Scopus database

2-s2.0-85141002172