Non-Detection of HC$_{11}$N toward TMC-1: Constraining the Chemistry of Large Carbon-Chain Molecules
| Autor: | Andrew M. Burkhardt, P. Brandon Carroll, Brett A. McGuire, Christopher N. Shingledecker, Anthony J. Remijan, Niklaus M. Dollhopf, Glen Langston, Barry E. Turner, Joanna F. Corby, Ryan A. Loomis, Shawn Thomas Booth |
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| Rok vydání: | 2016 |
| Předmět: |
Carbon chain
Astrochemistry Cyanopolyyne Chemistry Abundance (chemistry) Green Bank Telescope FOS: Physical sciences Astronomy and Astrophysics Nanotechnology 010402 general chemistry 01 natural sciences Astrophysics - Astrophysics of Galaxies 0104 chemical sciences chemistry.chemical_compound Space and Planetary Science Chemical physics Astrophysics of Galaxies (astro-ph.GA) 0103 physical sciences Molecule Non detection 010303 astronomy & astrophysics |
| DOI: | 10.48550/arxiv.1609.02570 |
| Popis: | Bell et al. (1997) reported the first detection of the cyanopolyyne HC$_{11}$N toward the cold dark cloud TMC-1; no subsequent detections have been reported toward any source. Additional observations of cyanopolyynes and other carbon-chain molecules toward TMC-1 have shown a log-linear trend between molecule size and column density, and in an effort to further explore the underlying chemical processes driving this trend, we have analyzed GBT observations of HC$_9$N and HC$_{11}$N toward TMC-1. Although we find an HC$_9$N column density consistent with previous values, HC$_{11}$N is not detected and we derive an upper limit column density significantly below that reported in Bell et al. Using a state-of-the-art chemical model, we have investigated possible explanations of non-linearity in the column density trend. Despite updating the chemical model to better account for ion-dipole interactions, we are not able to explain the non-detection of HC$_{11}$N, and we interpret this as evidence of previously unknown carbon-chain chemistry. We propose that cyclization reactions may be responsible for the depleted HC$_{11}$N abundance, and that products of these cyclization reactions should be investigated as candidate interstellar molecules. Comment: 10 pages, 7 figures, 3 tables, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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