G331.512-0.103: An Interstellar Laboratory for Molecular Synthesis I. The Ortho-to-para Ratios for CH$_3$OH and CH$_3$CN
| Autor: | Nicolas Reyes, Manuel Merello, Jacques Raymond Daniel Lépine, Diana Renata Gonçalves Gama, N. U. Duronea, Ricardo Finger, Lars Åke-Nyman, E. Mendoza, C. Hervías-Caimapo, Leonardo Bronfman |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Stereochemistry Ciencias Físicas Foundation (engineering) FOS: Physical sciences Astronomy and Astrophysics ISM [RADIO LINES] purl.org/becyt/ford/1.3 [https] 01 natural sciences Astrophysics - Astrophysics of Galaxies purl.org/becyt/ford/1 [https] Astronomía Space and Planetary Science MOLECULES [ISM] Astrophysics of Galaxies (astro-ph.GA) MEIO INTERESTELAR 0103 physical sciences 010306 general physics 010303 astronomy & astrophysics CIENCIAS NATURALES Y EXACTAS MOLECULAR PROCESSES |
| Zdroj: | CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP Mendoza, E, Bronfman, L, Duronea, N U, Lépine, J R D, Finger, R, Merello, M, Hervías-Caimapo, C, Gama, DI R G, Reyes, N & Åke-Nyman, L 2018, ' G331.512-0.103 : An Interstellar Laboratory for Molecular Synthesis. I. the Ortho-to-para Ratios for CH 3 OH and CH 3 CN ', Astrophysical Journal, vol. 853, no. 2, 152 . https://doi.org/10.3847/1538-4357/aaa1ec |
| DOI: | 10.48550/arxiv.1801.06019 |
| Popis: | Spectral line surveys reveal rich molecular reservoirs in G331.512-0.103, a compact radio source in the center of an energetic molecular outflow. In this first work, we analyse the physical conditions of the source by means of CH$_3$OH and CH$_3$CN. The observations were performed with the APEX telescope. Six different system configurations were defined to cover most of the band within (292-356) GHz; as a consequence we detected a forest of lines towards the central core. A total of 70 lines of $A/E$-CH$_3$OH and $A/E$-CH$_3$CN were analysed, including torsionally excited transitions of CH$_3$OH ($\nu_t$=1). In a search for all the isotopologues, we identified transitions of $^{13}$CH$_3$OH. The physical conditions were derived considering collisional and radiative processes. We found common temperatures for each $A$ and $E$ symmetry of CH$_3$OH and CH$_3$CN; the derived column densities indicate an $A/E$ equilibrated ratio for both tracers. The results reveal that CH$_3$CN and CH$_3$OH trace a hot and cold component with $T_k \sim$ 141 K and $T_k \sim$ 74 K, respectively. In agreement with previous ALMA observations, the models show that the emission region is compact ($\lesssim$ 5.5 arcsec) with gas density $n$(H$_2$)=(0.7-1) $\times$ 10$^7$ cm$^{-3}$. The CH$_3$OH/CH$_3$CN abundance ratio and the evidences for pre-biotic and complex organic molecules suggest a rich and active chemistry towards G331.512-0.103. Comment: 15 pages, 7 figures, 7 tables. Accepted for publication in The Astrophysical Journal |
| Databáze: | OpenAIRE |
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