Investigating the hot molecular core, G10.47+0.03: A pit of nitrogen-bearing complex organic molecules

¹ South-Western Institute for Astronomy Research (SWIFAR), Yunnan University (YNU), Kunming 650500, PR China
e-mail: wasim@ynu.edu.cn
² Indian Centre for Space Physics, 43 Chalantika, Garia Station Road, Kolkata 700084, India
³ Department of Space, Earth & Environment, Chalmers University of Technology, 412 96 Gothenburg, Sweden
⁴ Laboratoire d’astrophysique de Bordeaux, CNRS, Univ. Bordeaux, B18N, allée Geoffroy Saint-Hilaire, 33615 Pessac, France
⁵ Institute of Astronomy Space and Earth Science, AJ 316, Salt lake Sector II, Kolkata 700091, West Bengal, India
e-mail: ankan.das@gmail.com

Received: 17 April 2022
Accepted: 11 August 2022

Abstract

Context. Recent observations have shown that Nitrogen-bearing complex organic species are present in large quantities in star-forming regions. Thus, investigating the N-bearing species in a hot molecular core, such as G10.47+0.03, is crucial to understanding the molecular complexity in star-forming regions. They also allow us to investigate the chemical and physical processes that determine the many phases during the structural and chemical evolution of the source in star-forming regions.

Aims. The aim of this study is to investigate the spatial distribution and the chemical evolution states of N-bearing complex organic molecules in the hot core G10.47+0.03.

Methods. We used the Atacama Large Millimeter/submillimeter Array (ALMA) archival data of the hot molecular core G10.47+0.03. The extracted spectra were analyzed assuming local thermodynamic equilibrium (LTE). LTE methods are used to estimate the column density of observed species. Furthermore, robust methods such as Markov chain Monte Carlo (MCMC) and rotational diagram methods are implemented for molecules for which multiple transitions were identified to constrain the temperature and column density. Finally, we used the Nautilus gas-grain code to simulate the nitrogen chemistry in the hot molecular core. We carried out both 0D and 1D simulations of the source. We compared the simulated abundances with observational results.

Results. We report various transitions of nitrogen-bearing species (NH₂CN, HC₃N, HC₅N, C₂H₃CN, C₂H₅CN, and H₂NCH₂CN) together with some of their isotopologues and isomers. Besides this, we also report the identification of CH₃CCH and one of its isotopologues. We present detailed chemical simulation results to investigate the possible N-bearing chemistry in the source.

Conclusions. In this study, various transitions of nitrogen-bearing molecules are identified and discussed. The emissions originating from vinyl cyanide, ethyl cyanide, cyanoacetylene, and cyanamide are compact, which could be explained by our astrochemical modeling. Our 0D model shows that the chemistry of certain N-bearing molecules can be very sensitive to initial local conditions such as density or dust temperature. In our 1D model, simulated higher abundances of species such as HCN, HC₃N, and HC₅N toward the inner shells of the source confirm the observational findings.