<i>Trans-cis</i>molecular photoswitching in interstellar space

Cuadrado, S.; Goicoechea, J. R.; Roncero, Octavio; Aguado, Alfredo; Tercero, B.; Cernicharo, J.

doi:10.1051/0004-6361/201629913

Cited by 57 publications

(62 citation statements)

References 42 publications

(86 reference statements)

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“…A cold complex chemistry was discovered in B1-b via the detections of CH 3 OH, HCOOCH 3 , CH 3 CHO, trans-HCOOH, C 4 H, HNCO, and the H 2 C 3 O isomers (Sakai et al 2009a;Öberg et al 2010;López-Sepulcre et al 2015;Cuadrado et al 2016;Loison et al 2016), and tentatively CH 3 OCH 3 (Öberg et al 2010), as well as CH 3 O (Cernicharo et al 2012). These previous detections were all reported at levels well below the noise level obtained in our observations.…”

Section: B1-bsupporting

confidence: 54%

Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

Weaver

Laas

Zou

et al. 2017

ApJS

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Spectral line surveys are an indispensable tool for exploring the physical and chemical evolution of astrophysical environments due to the vast amount of data that can be obtained in a relatively short amount of time. We present deep, broadband spectral line surveys of 30 interstellar clouds using two broadband λ=1.3 mm receivers at the Caltech Submillimeter Observatory. This information can be used to probe the influence of physical environment on molecular complexity. We observed a wide variety of sources to examine the relative abundances of organic molecules as they relate to the physical properties of the source (i.e., temperature, density, dynamics, etc.). The spectra are highly sensitive, with noise levels 25 mK at a velocity resolution of ∼0.35kms −1 . In the initial analysis presented here, column densities and rotational temperatures have been determined for the molecular species that contribute significantly to the spectral line density in this wavelength regime. We present these results and discuss their implications for complex molecule formation in the interstellar medium.

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Section: B1-bsupporting

confidence: 54%

Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

Weaver

Laas

Zou

et al. 2017

ApJS

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“…3). To our knowledge, this is the second published detection of the higher energy cis-HCOOH conformer in space after the detection by Cuadrado et al (2016) towards the Orion bar. Three transitions from ketene, two in its ortho substate A&A proofs: manuscript no.…”

Section: Spectramentioning

confidence: 72%

Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud

Taquet

Wirström

Charnley

et al. 2017

A&A

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Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. We present the detection of the Complex Organic Molecules (COMs) acetaldehyde (CH 3 CHO) and methyl formate (CH 3 OCHO) as well as formic acid (HCOOH) and ketene (CH 2 CO), and the tentative detection of di-methyl ether (CH 3 OCH 3 ) towards the methanol hotspot of Barnard 5 located between two dense cores using the single dish OSO 20m, IRAM 30m, and NRO 45m telescopes. The high energy cis-conformer of formic acid is detected, suggesting that formic acid is mostly formed at the surface of interstellar grains and then evaporated. The detection of multiple transitions for each species allows us to constrain their abundances through LTE and non-LTE methods. All the considered COMs show similar abundances between ∼ 1 and ∼ 10 % relative to methanol depending on the assumed excitation temperature. The non-detection of glycolaldehyde, an isomer of methyl formate, with a [glycolaldehyde]/[methyl formate] abundance ratio lower than 6 %, favours gas phase formation pathways triggered by methanol evaporation. According to their excitation temperatures derived in massive hot cores, formic acid, ketene, and acetaldehyde have been designated as "lukewarm" COMs whereas methyl formate and di-methyl ether were defined as "warm" species. Comparison with previous observations of other types of sources confirms that "lukewarm" and "warm" COMs show similar abundances in low-density cold gas whereas the "warm" COMs tend to be more abundant than the "lukewarm" species in warm protostellar cores. This abundance evolution suggests either that "warm" COMs are indeed mostly formed in protostellar environments and/or that "lukewarm" COMs are efficiently depleted by increased hydrogenation efficiency around protostars.

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“…All of these polyene-containing molecules can, upon photon absorption, use the absorbed energy to flip their structure, between cis and trans forms, by rotation around a C=C double bond in their conjugated chains. Similarly, the formic acid molecule,

normalH - C \leq_{normalO}^{normalOH}

, can undergo a cis–trans conformational switch, around the single C−OH bond, a process that has recently been observed in the ISM [91]. Thus, there do exist channels that can evacuate excess energy from a nanoparticle and therefore increase its photo-stability.…”

Section: Nanoparticlesmentioning

confidence: 98%

Dust evolution, a global view I. Nanoparticles, nascence, nitrogen and natural selection … joining the dots

Jones

2016

R. Soc. open sci.

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The role and importance of nanoparticles for interstellar chemistry and beyond is explored within the framework of The Heterogeneous dust Evolution Model for Interstellar Solids (THEMIS), focusing on their active surface chemistry, the effects of nitrogen doping and the natural selection of interesting nanoparticle sub-structures. Nanoparticle-driven chemistry, and in particular the role of intrinsic epoxide-type structures, could provide a viable route to the observed gas phase OH in tenuous interstellar clouds en route to becoming molecular clouds. The aromatic-rich moieties present in asphaltenes probably provide a viable model for the structures present within aromatic-rich interstellar carbonaceous grains. The observed doping of such nanoparticle structures with nitrogen, if also prevalent in interstellar dust, could perhaps have important and observable consequences for surface chemistry and the formation of precursor pre-biotic species.

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Trans-cismolecular photoswitching in interstellar space

Cited by 57 publications

References 42 publications

Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud

Dust evolution, a global view I. Nanoparticles, nascence, nitrogen and natural selection … joining the dots

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