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
p1762
bright-rimmed clouds
class-i
p617
astronomical journal
ghz methanol masers
1995
molecular cloud cores
v110
llanen md
infrared dark clouds
1995
star-forming regions
publications of the astronomical society of the pacific
parallaxes
v107
cutcheon wh
trigonometric
fu-orionis stars
young stellar population
Författare
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 10 904-923Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1134/s106377291610005x