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.
fu-orionis stars
extended green objects
astronomical journal
p617
v107
star-forming regions
class-i
cutcheon wh
llanen md
bright-rimmed clouds
1995
p1762
young stellar population
molecular cloud cores
publications of the astronomical society of the pacific
v110
infrared dark clouds
parallaxes
1995
ghz methanol masers
trigonometric
Astronomy & Astrophysics
Författare
L. E. Pirogov
Russian Academy of Sciences
Valery Shulga
Institute of Radio Astronomy National Academy of Sciences of Ukraine
I Zinchenko
Russian Academy of Sciences
Peter Zemlyanukha
Russian Academy of Sciences
Lobachevsky University
Oleksii Patoka
Institute of Radio Astronomy National Academy of Sciences of Ukraine
Magnus Thomasson
Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium
Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik
Astronomy Reports
1063-7729 (ISSN) 1562-6881 (eISSN)
Vol. 60 10 904-923Ämneskategorier
Astronomi, astrofysik och kosmologi
DOI
10.1134/s106377291610005x