Discovery of H2CCCH+ in TMC-1

By Keith Cowing
Status Report
July 6, 2023
Filed under , , , ,
Discovery of H2CCCH+ in TMC-1
Pure rotational transition (J Ka′Kc′ ← J ′′ Ka′′Kc′′ = 818 ← 717) of H2CCCH+ recorded using the double resonance spectroscopic scheme. For this measurement, the IR laser frequency (red arrow) was kept fixed on resonance with the 919 ← 818 rovibrational transition within the ν1 band. — astro-ph.GA

Based on a novel laboratory method, 14 mm-wave lines of the molecular ion H2CCCH+ have been measured in high resolution, and the spectroscopic constants of this asymmetric rotor determined with high accuracy.

Using the Yebes 40 m and IRAM 30 m radio telescopes, we detect four lines of H2CCCH+ towards the cold dense core TMC-1. With a dipole moment of about 0.55 Debye obtained from high-level ab initio calculations, we derive a column density of 5.4±1×1011 cm−2 and 1.6±0.5×1011 cm−2 for the ortho and para species, respectively, and an abundance ratio N(H2CCC)/N(H2CCCH+)= 2.8±0.7. The chemistry of H2CCCH+ is modelled using the most recent chemical network for the reactions involving the formation of H2CCCH+.

We find a reasonable agreement between model predictions and observations, and new insights into the chemistry of C3 bearing species in TMC-1 are obtained.

W. G. D. P. Silva, J. Cernicharo, S. Schlemmer, N. Marcelino, J.-C. Loison, M. Agúndez, D. Gupta, V. Wakelam, S. Thorwirth, C. Cabezas, B. Tercero, J. L. Doménech, R. Fuentetaja, W.-J. Kim, P. de Vicente, O. Asvany

Subjects: Astrophysics of Galaxies (astro-ph.GA); Chemical Physics (physics.chem-ph)
Cite as: arXiv:2307.01733 [astro-ph.GA] (or arXiv:2307.01733v1 [astro-ph.GA] for this version)
Submission history
From: Divita Gupta
[v1] Tue, 4 Jul 2023 14:04:34 UTC (2,208 KB)
Astrobiology, Astrochemistry

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