Detections Of Interstellar 2-cyanopyrene And 4-cyanopyrene In TMC-1
Polycyclic aromatic hydrocarbons (PAHs) are among the most ubiquitous compounds in the universe, accounting for up to ~25% of all interstellar carbon. Since most unsubstituted PAHs do not possess permanent dipole moments, they are invisible to radio astronomy.
Constraining their abundances relies on the detection of polar chemical proxies, such as aromatic nitriles. We report the detection of 2- and 4-cyanopyrene, isomers of the recently detected 1-cyanopyrene. We find that these isomers are present in an abundance ratio of ~2:1:2, which mirrors the number of equivalent sites available for CN addition.
We conclude that there is evidence that the cyanopyrene isomers formed by direct CN addition to pyrene under kinetic control in hydrogen-rich gas at 10 K and discuss constraints on the H/CN ratio for PAHs in TMC-1.
Gabi Wenzel, Thomas H. Speak, P. Bryan Changala, Reace H. J. Willis, Andrew M. Burkhardt, Shuo Zhang, Edwin A. Bergin, Alex N. Byrne, Steven B. Charnley, Zachary T. P. Fried, Harshal Gupta, Eric Herbst, Martin S. Holdren, Andrew Lipnicky, Ryan A. Loomis, Christopher N. Shingledecker, Ci Xue, Anthony J. Remijan, Alison E. Wendlandt, Michael C. McCarthy, Ilsa R. Cooke, Brett A. McGuire
Comments: Submitted version to comply with licensing agreements
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2410.00670 [astro-ph.GA] (or arXiv:2410.00670v2 [astro-ph.GA] for this version)
https://doi.org/10.48550/arXiv.2410.00670
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Submission history
From: Brett McGuire
[v1] Tue, 1 Oct 2024 13:28:42 UTC (5,999 KB)
[v2] Fri, 4 Oct 2024 19:22:12 UTC (12,252 KB)
Astrobiology, Astrochemistry,