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 10 904-923

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1134/s106377291610005x

Mer information

Senast uppdaterat

2018-04-16