A Search For Heterocycles in GOTHAM Observations Of TMC-1

By Keith Cowing
April 11, 2022
Filed under
A Search For Heterocycles in GOTHAM Observations Of TMC-1
Visualization of a two-dimensional projection of the chemical embedding space spanned by: the current chemical inventory of TMC-1 (blue); and the proposed heterocyclic species (orange). Representative structures of indicative molecules annotate how chemical complexity in this source is traversed and divided: molecules such as the cyanopolyynes extend from the top to the bottom on the right, connecting with single-ring heterocycles such as furan toward the bottom. On the left, two-ring species such as cyanonaphthalene (not pictured) and their heterocyclic analogues.

We have conducted an extensive search for nitrogen-, oxygen- and sulfur-bearing heterocycles toward Taurus Molecular Cloud 1 (TMC-1) using the deep, broadband centimeter-wavelength spectral line survey of the region from the GOTHAM large project on the Green Bank Telescope.

Despite their ubiquity in terrestrial chemistry, and the confirmed presence of a number of cyclic and polycyclic hydrocarbon species in the source, we find no evidence for the presence of any heterocyclic species. Here, we report the derived upper limits on the column densities of these molecules obtained by Markov Chain Monte Carlo (MCMC) analysis and compare this approach to traditional single-line upper limit measurements. We further hypothesize why these molecules are absent in our data, how they might form in interstellar space, and the nature of observations that would be needed to secure their detection.

Timothy J. Barnum, Mark A. Siebert, Kin Long Kelvin Lee, Ryan A. Loomis, P. Bryan Changala, Steven B. Charnley, Madelyn L. Sita, Ci Xue, Anthony J. Remijan, Andrew M. Burkhardt, Brett A. McGuire, Ilsa R. Cooke

Comments: Accepted in the Journal of Physical Chemistry A
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2204.04744 [astro-ph.GA] (or arXiv:2204.04744v1 [astro-ph.GA] for this version)
Submission history
From: Brett McGuire
[v1] Sun, 10 Apr 2022 18:44:16 UTC (4,580 KB)
Astrobiology, Astrochemistry

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