| Full text | |
| Author(s): |
Santos, Julia C.
[1, 2]
;
Bronfman, Leonardo
[3]
;
Mendoza, Edgar
[1, 4]
;
Lepine, Jacques R. D.
[1]
;
Duronea, Nicolas U.
[5, 6]
;
Merello, Manuel
[3]
;
Finger, Ricardo
[3]
Total Authors: 7
|
| Affiliation: | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, Sao Paulo, SP - Brazil
[2] Leiden Univ, Leiden Observ, Lab Astrophys, POB 9513, NL-2300 RA Leiden - Netherlands
[3] Univ Chile, Dept Astron, Casilla 36-D, Santiago - Chile
[4] Univ Fed Rio de Janeiro, Observ Valongo, Ladeira do Pedro Antonio 43, Rio De Janeiro, RJ - Brazil
[5] Inst Astrofis La Plata UNLP CONICET, La Plata - Argentina
[6] Univ Nacl La Plata, Fac Ciencias Astron & Geofis, Paseo Bosque S-N, RA-1900 La Plata - Argentina
Total Affiliations: 6
|
| Document type: | Journal article |
| Source: | ASTROPHYSICAL JOURNAL; v. 925, n. 1 JAN 1 2022. |
| Web of Science Citations: | 0 |
| Abstract | |
A spectral survey of methyl acetylene (CH3CCH) was conducted toward the hot molecular core/outflow G331.512-0.103. Our APEX observations allowed the detection of 41 uncontaminated rotational lines of CH3CCH in the frequency range between 172 and 356 GHz. Through an analysis under the local thermodynamic equilibrium assumption, by means of rotational diagrams, we determined T (exc) = 50 +/- 1 K, N(CH3CCH) = (7.5 +/- 0.4) x 10(15) cm(2), X{[}CH3CCH/H-2] approximate to (0.8-2.8) x 10(-8), and X{[}CH3CCH/CH3OH] approximate to 0.42 +/- 0.05 for an extended emitting region (similar to 10 `'). The relative intensities of the K = 2 and K = 3 lines within a given K-ladder are strongly negatively correlated to the transitions' upper J quantum number (r = -0.84). Pure rotational spectra of CH3CCH were simulated at different temperatures, in order to interpret this observation. The results indicate that the emission is characterized by a nonnegligible temperature gradient with upper and lower limits of similar to 45 and similar to 60 K, respectively. Moreover, the line widths and peak velocities show an overall strong correlation with their rest frequencies, suggesting that the warmer gas is also associated with stronger turbulence effects. The K = 0 transitions present a slightly different kinematic signature than the remaining lines, indicating that they might be tracing a different gas component. We speculate that this component is characterized by lower temperatures and therefore larger sizes. Moreover, we predict and discuss the temporal evolution of the CH3CCH abundance using a two-stage zero-dimensional model of the source constructed with the three-phase Nautilus gas-grain code. (AU) | |
| FAPESP's process: | 14/22095-6 - ACHEMOS: astrochemistry of our origins, a comprehensive study of the prebiotic chemistry in pre-stellar regions |
| Grantee: | Edgar Fabián Mendoza Rodríguez |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |