Multifrequency Studies of Massive Cores with Complex Spatial and Kinematic Structures
Artikel i vetenskaplig tidskrift, 2016

Five regions of massive-star formation have been observed in various molecular lines in the frequency range similar to 85-89 GHz. The studied regions comprise dense cores, which host young stellar objects. The physical parameters of the cores are estimated, including the kinetic temperatures (similar to 20-40 K), the sizes of the emitting regions (similar to 0.1-0.6 pc), and the virial masses (similar to 40-500 M-circle dot). The column densities and abundances of various molecules are calculated assuming Local Thermodynamical Equilibrium(LTE). The core in 99.982+4.17, which is associated with the weakest IRAS source, is characterized by reduced molecular abundances. The molecular line widths decrease with increasing distance from the core centers (b). For b greater than or similar to 0.1 pc, the dependences Delta V (b) are close to power laws (alpha b(-p)), where p varies from similar to 0.2 to similar to 0.5, depending on the object. In four cores, the asymmetries of the optically thick HCN(1-0) and HCO+(1-0) lines indicates systematic motions along the line of sight: collapse in two cores and expansion in two others. Approximate estimates of the accretion rates in the collapsing cores indicate that the forming stars have masses exceeding the solar mass.

Astronomy & Astrophysics

extended green objects


bright-rimmed clouds



astronomical journal

ghz methanol masers


molecular cloud cores


llanen md

infrared dark clouds


star-forming regions

publications of the astronomical society of the pacific



cutcheon wh


fu-orionis stars

young stellar population


L. E. Pirogov

Russian Academy of Sciences

Valery Shulga

National Academy of Sciences in Ukraine

I Zinchenko

Russian Academy of Sciences

Peter Zemlyanukha

Lobachevsky University

Russian Academy of Sciences

Oleksii Patoka

National Academy of Sciences in Ukraine

M. Tomasson

Student vid Chalmers

Astronomy Reports

1063-7729 (ISSN) 1562-6881 (eISSN)

Vol. 60 10 904-923


Astronomi, astrofysik och kosmologi



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