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Multifrequency Studies of Massive Cores with Complex Spatial and Kinematic Structures

L. E. Pirogov ; V. M. Shul'ga ; , II Zinchenko ; P. M. Zemlyanukha ; A. N. Patoka ; Magnus Thomasson (Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik ; Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium)
Astronomy Reports (1063-7729). Vol. 60 (2016), 10, p. 904-923.
[Artikel, refereegranskad vetenskaplig]

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.

Nyckelord: star-forming regions, ghz methanol masers, young stellar population, extended green objects, molecular cloud cores, infrared dark clouds, bright-rimmed clouds, fu-orionis stars, class-i, trigonometric, parallaxes, Astronomy & Astrophysics, cutcheon wh, 1995, astronomical journal, v110, p1762, llanen md, 1995, publications of the astronomical society of the pacific, v107, p617



Denna post skapades 2016-12-09. Senast ändrad 2017-01-31.
CPL Pubid: 245994

 

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Institutioner (Chalmers)

Institutionen för rymd- och geovetenskap, Radioastronomi och astrofysik (2010-2017)
Institutionen för rymd- och geovetenskap, Onsala rymdobservatorium (2010-2017)

Ämnesområden

Astronomi, astrofysik och kosmologi

Chalmers infrastruktur