Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1

<jats:title>Abstract</jats:title> <jats:p>Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in the dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional observations of an ongoing, large-s...

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Main Authors: Kelvin Lee, Kin Long, Changala, P Bryan, Loomis, Ryan A, Burkhardt, Andrew M, Xue, Ci, Cordiner, Martin A, Charnley, Steven B, McCarthy, Michael C, McGuire, Brett A
Other Authors: Massachusetts Institute of Technology. Department of Chemistry
Format: Article
Language:English
Published: American Astronomical Society 2022
Online Access:https://hdl.handle.net/1721.1/141110
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author Kelvin Lee, Kin Long
Changala, P Bryan
Loomis, Ryan A
Burkhardt, Andrew M
Xue, Ci
Cordiner, Martin A
Charnley, Steven B
McCarthy, Michael C
McGuire, Brett A
author2 Massachusetts Institute of Technology. Department of Chemistry
author_facet Massachusetts Institute of Technology. Department of Chemistry
Kelvin Lee, Kin Long
Changala, P Bryan
Loomis, Ryan A
Burkhardt, Andrew M
Xue, Ci
Cordiner, Martin A
Charnley, Steven B
McCarthy, Michael C
McGuire, Brett A
author_sort Kelvin Lee, Kin Long
collection MIT
description <jats:title>Abstract</jats:title> <jats:p>Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in the dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional observations of an ongoing, large-scale, high-sensitivity spectral line survey (GOTHAM) at centimeter wavelengths toward this source, we have used a combination of spectral stacking, Markov Chain Monte Carlo (MCMC), and matched filtering techniques to detect 2-cyanocyclopentadiene, a low-lying isomer of 1-cyanocyclopentadiene, which was recently discovered there by the same methods. The new observational data also yield a considerably improved detection significance for the more stable isomer and evidence for several individual transitions between 23–32 GHz. Through our MCMC analysis, we derive cospatial, total column densities of 8.3 × 10<jats:sup>11</jats:sup> and 1.9 × 10<jats:sup>11</jats:sup> cm<jats:sup>−2</jats:sup> for 1- and 2-cyanocyclopentadiene, respectively, corresponding to a ratio of ∼4.4 favoring the former. The derived abundance ratios point toward a common formation pathway—most likely being cyanation of cyclopentadiene by analogy to benzonitrile.</jats:p>
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spelling mit-1721.1/1411102023-02-14T19:57:48Z Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1 Kelvin Lee, Kin Long Changala, P Bryan Loomis, Ryan A Burkhardt, Andrew M Xue, Ci Cordiner, Martin A Charnley, Steven B McCarthy, Michael C McGuire, Brett A Massachusetts Institute of Technology. Department of Chemistry <jats:title>Abstract</jats:title> <jats:p>Using radio observations with the Green Bank Telescope, evidence has now been found for a second five-membered ring in the dense cloud Taurus Molecular Cloud-1 (TMC-1). Based on additional observations of an ongoing, large-scale, high-sensitivity spectral line survey (GOTHAM) at centimeter wavelengths toward this source, we have used a combination of spectral stacking, Markov Chain Monte Carlo (MCMC), and matched filtering techniques to detect 2-cyanocyclopentadiene, a low-lying isomer of 1-cyanocyclopentadiene, which was recently discovered there by the same methods. The new observational data also yield a considerably improved detection significance for the more stable isomer and evidence for several individual transitions between 23–32 GHz. Through our MCMC analysis, we derive cospatial, total column densities of 8.3 × 10<jats:sup>11</jats:sup> and 1.9 × 10<jats:sup>11</jats:sup> cm<jats:sup>−2</jats:sup> for 1- and 2-cyanocyclopentadiene, respectively, corresponding to a ratio of ∼4.4 favoring the former. The derived abundance ratios point toward a common formation pathway—most likely being cyanation of cyclopentadiene by analogy to benzonitrile.</jats:p> 2022-03-10T15:26:58Z 2022-03-10T15:26:58Z 2021 2022-03-10T15:22:51Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/141110 Kelvin Lee, Kin Long, Changala, P Bryan, Loomis, Ryan A, Burkhardt, Andrew M, Xue, Ci et al. 2021. "Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1." The Astrophysical Journal Letters, 910 (1). en 10.3847/2041-8213/ABE764 The Astrophysical Journal Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Astronomical Society The American Astronomical Society
spellingShingle Kelvin Lee, Kin Long
Changala, P Bryan
Loomis, Ryan A
Burkhardt, Andrew M
Xue, Ci
Cordiner, Martin A
Charnley, Steven B
McCarthy, Michael C
McGuire, Brett A
Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title_full Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title_fullStr Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title_full_unstemmed Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title_short Interstellar Detection of 2-cyanocyclopentadiene, C 5 H 5 CN, a Second Five-membered Ring toward TMC-1
title_sort interstellar detection of 2 cyanocyclopentadiene c 5 h 5 cn a second five membered ring toward tmc 1
url https://hdl.handle.net/1721.1/141110
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