Study of Methanol Emission at Frequencies 216—234 GHz In Selected Regions of The High Mass Protostellar Object G12.89+0.49 (IRAS18089-1732)
Year: 2025
Type: conference-paper
Abstract: Preliminary results of the study of molecular spectra of three regions of the massive protostellar object G12.89+0.49, observed with the ALMA interferometer in the frequency range of 216-234 GHz, are presented. Regions of size 0.15ʺ × 0.15ʺ are identified along the disk plane (MM1-1, MM1-2 and MM1-3). In the region MM1-1, which is the richest with lines, 28 methanol lines are identified in the spectra. A significant difference was revealed in the widths of the methanol lines: in MM1-1 FWHM = 5-7 km/s, in MM1-2 and MM1-3 3- 4 km/s, and in the radial velocities: in MM1-1 and MM1-2 Vlsr = 31-32 km/s, in MM1-3 35-36 km/s. Based on the estimates of the physical parameters of the regions under consideration, carried out using the large velocity gradient approximation, it was concluded that most of the observed methanol lines correspond to transitions that are excited, with a probability of 95 %, in the outer parts of the disk with the parameters: gas kinetic temperature ≥ 140 K, gas number density ≥ 105 cm−3, methanol column density ≥ 1018 cm−2, methanol abundance ≥ 10−6. At the same time, in MM1-1 and MM1-2, lines are observed corresponding to transitions of the J6−J7 Evt = 1 series, which, according to our estimates, are excited in a hotter ≥ 190 K and, possibly, denser part of the disk.
Authors: S. V. Salii, A. M. Sobolev, D. A. Ladeyschikov, H. Z. Yu, Sh.-Y. Liu
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4412584615