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.

parallaxes

p617

publications of the astronomical society of the pacific

v107

1995

molecular cloud cores

fu-orionis stars

ghz methanol masers

extended green objects

star-forming regions

v110

trigonometric

class-i

astronomical journal

infrared dark clouds

p1762

bright-rimmed clouds

1995

llanen md

Astronomy & Astrophysics

young stellar population

cutcheon wh

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

Magnus Thomasson

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium

Astronomy Reports

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

Vol. 60 10 904-923

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1134/s106377291610005x

Mer information

Senast uppdaterat

2020-12-04