National Research Lobachevsky State University of Nizhny Novgorod
UDK 53
UDK 520
UDK 521
UDK 523
UDK 524
UDK 52-1
UDK 52-6
GRNTI 41.00
GRNTI 29.35
GRNTI 29.31
GRNTI 29.33
GRNTI 29.27
GRNTI 29.05
OKSO 03.06.01
OKSO 03.05.01
OKSO 03.04.03
BBK 2
BBK 223
TBK 614
TBK 6135
BISAC SCI004000 Astronomy
BISAC SCI005000 Physics / Astrophysics
Massive stars play an important role in the Universe. Unlike low-mass stars, the formation of these objects located at great distances is still unclear. It is expected to be governed by some combination of self-gravity, turbulence, and magnetic fields. Our aim is to study the chemical and physical conditions of dense clumps in several high-mass star-forming regions. We performed observations towards 5 high-mass star-forming regions (L1287, S187, S231, DR 21(OH), NGC 7538) with the IRAM 30-m telescope. We covered the 2-3 and 4 mm wavelength bands and analysed the lines of HCN, HNC, HCO$^+$, HC$_3$N, HNCO, OCS, CS, SiO, SO$_2$, and SO. Using the astrodendro algorithm on the 850 $\mu$m dust emission data from the SCUBA Legacy catalogue, we identified dense gas clumps and assessed their masses, H$_2$ column densities, and sizes. Furthermore, the kinetic temperatures, molecular abundances and dynamical state were obtained. The Red Midcourse Space Experiment Source survey (RMS) was utilized to identify the types of clumps. A total of 20 clumps were identified. We found no significant correlation between line width and size, but the linewidth-mass and mass-size relationships are strongly correlated. Virial analysis indicated that the clumps with H II regions and young stellar objects (YSOs) are gravitationally bound. Furthermore, it was suggested that significant magnetic fields provide additional support for clump stability. Molecular abundances show a decreasing trend from YSOs to submm and H II regions.
ISM: abundances, molecules; stars: formation, massive; astrochemistry
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