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arXiv · 2010.04710

Tentative detection of HC5NH+ in TMC-1

N. Marcelino·M. Agundez·B. Tercero·C. Cabezas·C. Bermudez·J. D. Gallego·P. de Vicente·J. Cernicharo
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Abstract

Using the Yebes 40m radio telescope, we report the detection of a series of seven lines harmonically related with a rotational constant B0=1295.81581 +/- 0.00026 MHz and a distortion constant D0=27.3 +/- 0.5 Hz towards the cold dense cloud TMC-1. Ab initio calculations indicate that the best possible candidates are the cations HC5NH+ and NC4NH+. From a comparison between calculated and observed rotational constants and other arguments based on proton affinities and dipole moments, we conclude that the best candidate for a carrier of the observed lines is the protonated cyanodiacetylene cation, HC5NH+. The HC5N/HC5NH+ ratio derived in TMC-1 is 240, which is very similar to the HC3N/HC3NH+ ratio. Results are discussed in the framework of a chemical model for protonated molecules in cold dense clouds.

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N. Marcelino, M. Agundez, B. Tercero, C. Cabezas, C. Bermudez, J. D. Gallego, P. de Vicente, J. Cernicharo. 2020-10-09. Tentative detection of HC5NH+ in TMC-1. https://doi.org/10.1051/0004-6361/202039251

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