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Duronea, N. U. ^{[1, 2]} ; Bronfman, L. ^[3] ; Mendoza, E. ^[4] ; Merello, M. ^[4] ; Finger, R. ^[3] ; Reyes, N. ^{[3, 5]} ; Hervias-Caimapo, C. ^[6] ; Faure, A. ^[7] ; Cappa, C. E. ^[8] ; Arna, E. M. ^[8] ; Lepine, J. R. D. ^[4] ; Kleiner, I ^[9] ; Nyman, L-A ^[10]

Afiliação do(s) autor(es)

^[1] CCT La Plata, CONICET, Inst Argentino Radioastron, CC 5, RA-1894 Villa Elisa, Prov De Bs As - Argentina

^[2] CIC, La Plata, Prov De Bs As - Argentina

^[3] Univ Chile, Dept Astron, Casilla 36, Santiago - Chile

^[4] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo, SP - Brazil

^[5] Univ Chile, Dept Ingn Elect, Santiago - Chile

^[6] Florida State Univ, Dept Phys, Tallahassee, FL 32306 - USA

^[7] Univ Grenoble Alpes, IPAG, CNRS, F-38000 Grenoble - France

^[8] Univ Nacl La Plata, Fac Ciencias Astron & Geofis, Paseo Bosque S-N, RA-1900 La Plata, Buenos Aires - Argentina

^[9] Univ Paris Est Creteil & Paris Diderot, UMR 7583, CNRS, LISA, 61 Av Gen Gaulle, F-94010 Creteil - France

^[10] Joint ALMA Observ, JAO Alonso de Cordova 31070, Vitacura, Santiago De Chi - Chile

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 489, n. 2, p. 1519-1532, OCT 2019.
• Citações Web of Science: 0

Resumo

Using APEX-1 and APEX-2 observations, we have detected and studied the rotational lines of the HC3N molecule (cyanoacetylene) in the powerful outflow/hot molecular core G331.512-0.103. We identified 31 rotational lines at J levels between 24 and 39; 17 of them in the ground vibrational state v = 0 (9 lines corresponding to the main C isotopologue and 8 lines corresponding to the C-13 isotopologues), and 14 in the lowest vibrationally excited state v(7) = 1. Using local thermodynamic equilibrium (LTE)-based population diagrams for the beam-diluted v = 0 transitions, we determined T-exc = 85 +/- 4 K and N(HC3N) = (6.9 +/- 0.8) x 1014 cm(-2), while for the beam-diluted v7 = 1 transitions we obtained T-exc = 89 +/- 10 K and N(HC3N) = (2 +/- 1) x 10(15) cm(-2). Non-LTE calculations using H-2 collision rates indicate that the HC3N emission is in good agreement with LTE-based results. From the non-LTE method, we estimated T-kin similar or equal to 90 K, n(H-2) similar or equal to 2 x 10(7) cm(-3) for a central core of 6 arcsec in size. A vibrational temperature in the range from 130 to 145 K was also determined, values which are very likely lower limits. Our results suggest that rotational transitions are thermalized, while infrared radiative pumping processes are probably more efficient than collisions in exciting the molecule to the vibrationally excited state v7 = 1. Abundance ratios derived under LTE conditions for the C-13 isotopologues suggest that the main formation pathway of HC3N is C2H2 + CN -> HC3N + H. (AU)

• Processo FAPESP: 14/22095-6 - ACHEMOS: astroquímica da nossa origem, um estudo abrangente da química prebiótica em regiões pré-estelares
• Beneficiário: Edgar Fabián Mendoza Rodríguez
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado