Isocyanic acid (HNCO) in the hot molecular core G331.512-0.103: observations and chemical modelling

Canelo, Carla Martinez; Bronfman, L.; Mendoza, Edgar; Duronea, N. U.; Merello, Manuel; Carvajal, M.; Friaça, Amâncio César Santos; Lépine, J. R. D.

doi:10.1093/mnras/stab1163

Cited by 12 publications

(14 citation statements)

References 89 publications

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“…Similar implications were found in observations and models of HNCO, another tracer associated with outflow dynamics and chemistry (e.g. Rodríguez-Fernández et al 2010;Velilla Prieto et al 2015;Canelo et al 2021).…”

Section: Comparison With Observational Studiessupporting

confidence: 82%

The Si + SO2 collision and an extended network of neutral–neutral reactions between silicon and sulphur bearing species

Campanha

Mendoza

Silva

et al. 2022

Monthly Notices of the Royal Astronomical Society

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The Si+SO2 reaction is investigated to verify its impact on the abundances of molecules with astrochemical interest, such as SiS, SiO, SO and others. According to our results Si(3P) and SO2 react barrierlessly yielding only the monoxides SO and SiO as products. No favourable pathway has been found leading to other products, and this reaction should not contribute to SiS abundance. Furthermore, it is predicted that SiS is stable in collisions with O2, and that S(3P)+SiO2 and O(3P)+OSiS will also produce SO+SiO. Using these results and gathering further experimental and computational data from the literature, we provide an extended network of neutral-neutral reactions involving Si- and S-bearing molecules. The effects of these reactions were examined in a protostellar shock model, using the Nautilus gas-grain code. This consisted in simulating the physicochemical conditions of a shocked gas evolving from (i primeval cold core, (ii the shock region itself, (iii and finally the gas bulk conditions after the passage of the shock. Emphasising on the cloud ages and including systematically these chemical reactions, we found that [SiS/H2] can be of the order of ∼ 10−8 in shocks that evolves from clouds of t = 1 × 106 yr, whose values are mostly affected by the SiS+O $\longrightarrow$SiO+S reaction. Perspectives on further models along with observations are discussed in the context of sources harbouring molecular outflows.

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Section: Comparison With Observational Studiessupporting

confidence: 82%

The Si + SO2 collision and an extended network of neutral–neutral reactions between silicon and sulphur bearing species

Campanha

Mendoza

Silva

et al. 2022

Monthly Notices of the Royal Astronomical Society

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“…The simplest one, isocyanate radical (NCO), has been observed relatively recently in the line survey of L483 (Marcelino et al 2018), while isocyanic acid (HNCO) belongs among the early molecules detected in the universe dating back to 1972 (Snyder & Buhl 1972;Buhl et al 1972). HNCO is a well established interstellar molecule observed in the direction of a variety of sources such as TMC-1 (Brown 1981), IRAS 16293-2422 (Bisschop et al 2008;Coutens et al 2016), L483 (Marcelino et al 2018), NGC 6334I ⋆ Tables A.2, A.3, A.5, and A.6 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/ (Ligterink et al 2020), G31.41+0.31 (Colzi et al 2021), Serpens SMM1 (Ligterink et al 2021), and G331.512-0.103 (Canelo et al 2021). Its protonated form, H 2 NCO + , had been tentatively observed in Sgr B2 by Gupta et al (2013), but later on its presence in space has been confirmed by Marcelino et al (2018).…”

Section: Introductionmentioning

confidence: 99%

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

Vávra

Kolesníková

Беллоче

et al. 2022

A&A

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Context. The interstellar detections of isocyanic acid (HNCO), methyl isocyanate (CH 3 NCO), and very recently also ethyl isocyanate (C 2 H 5 NCO), open the question of the possible detection of vinyl isocyanate (C 2 H 3 NCO) in the interstellar medium. There are only low-frequency spectroscopic data (< 40 GHz) available for this species in the literature. This makes predictions at higher frequencies rather uncertain hampering its search in space by millimeter wave astronomy. Aims. The aim of the present study is, on one hand, to extend the laboratory rotational spectrum of vinyl isocyanate into the millimeter wave region and, on the other hand, to undertake a first check 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. The pure rotational spectrum of vinyl isocyanate was recorded in the frequency regions 127.5-218 and 285-330 GHz using the Prague millimeter 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 CH 3 NCO:C 2 H 5 NCO 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 C 2 H 3 NCO:C 2 H 5 NCO should be rather less than unity. Even though vinyl isocyanate was not detected toward Sgr B2(N), results of this work represent a significant improvement on previous low-frequency studies and will allow the astronomical community to continue in searching for this species in the universe.

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“…The original intensity, obtained in a scale of antenna temperature corrected for atmospheric attenuation (T A ), was converted to the main-beam temperature (T mb ) scale using the main-beam efficiencies η mb = 0.80 for SEPIA180 1 , and η mb = 0.75 and 0.73 for APEX-1 and APEX-2, respectively 2 (e.g. Canelo et al 2021). The Half Power Beam Width (HPBW) values vary between ∼17-39 .…”

Section: Observationsmentioning

confidence: 99%

“…The model consists of two zero-dimensional steps (i.e., the physical properties of the source are uniform and static), comprising the dark-cloud and the hotcore phases of star formation. The 1 st step, representing an initial dark-cloud phase, was computed using the elemental abundances listed in Table 6, as was computed in previous works about the chemistry of HNCO in G331 (Canelo et al 2021). For the physical parameters, we adopted a gas temperature and density of 10 K and 1 × 10 4 cm −3 , respectively.…”

Section: Chemical Modelingmentioning

confidence: 99%

“…Observations with the Atacama Large Millimeter/submillimeter Array (ALMA) of the SiO(8-7), H 13 CO + (4-3), HCO + (4-3) and CO(3-2) transitions revealed an expanding bubble geometry driven by stellar winds, which probably arises from the protostar confined in a compact H II region of ∼5 arcsec (projected size of ∼0.2 pc) (Merello et al 2013a). Its emission spectrum exhibits great chemical lavishness, from common radicals and carbon-chain molecules to prebiotic and com-plex organic species (Merello et al 2013a,b;Mendoza et al 2018;Duronea et al 2019;Hervías-Caimapo et al 2019;Canelo et al 2021). All those factors make G331 an exquisite source for astrochemical investigations by means of spectral surveys in sub-mm wavelenghts.…”

Section: Introductionmentioning

confidence: 99%

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A spectral survey of CH3CCH in the Hot Molecular Core G331.512-0.103

Santos,

Bronfman,

Mendoza

et al. 2022

Preprint

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A spectral survey of methyl acetylene (CH 3 CCH) was conducted toward the hot molecular core/outflow G331.512-0.103. Our APEX observations allowed the detection of 41 uncontaminated rotational lines of CH 3 CCH in the frequency range between 172-356 GHz. Through an analysis under the local thermodynamic equilibrium assumption, by means of rotational diagrams, we determined.05 for an extended emitting region (∼10 ). The relative intensities of the K=2 and K=3 lines within a given K-ladder are strongly negatively correlated to the transitions' upper J quantum-number (r=-0.84). Pure rotational spectra of CH 3 CCH were simulated at different temperatures, in order to interpret this observation. The results indicate that the emission is characterized by a non-negligible temperature gradient with upper and lower limits of ∼45 and ∼60 K, respectively. Moreover, the line widths and peak velocities show an overall strong correlation with their rest frequencies, suggesting that the warmer gas is also associated with stronger turbulence effects. The K=0 transitions present a slightly different kinematic signature than the remaining lines, indicating that they might be tracing a different gas component. We speculate that this component is characterized by lower temperatures, and therefore larger sizes. Moreover, we predict and discuss the temporal evolution of the CH 3 CCH abundance using a two-stage zero-dimensional model of the source constructed with the three-phase Nautilus gas-grain code.

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Isocyanic acid (HNCO) in the hot molecular core G331.512-0.103: observations and chemical modelling

Cited by 12 publications

References 89 publications

The Si + SO2 collision and an extended network of neutral–neutral reactions between silicon and sulphur bearing species

The Si + SO2 collision and an extended network of neutral–neutral reactions between silicon and sulphur bearing species

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

A spectral survey of CH3CCH in the Hot Molecular Core G331.512-0.103

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