2022MNRAS.515.2445Z -
Mon. Not. R. Astron. Soc., 515, 2445-2463 (2022/September-2)
Fragmented atomic shell around S187 H II region and its interaction with molecular and ionized gas.
ZEMLYANUKHA P., ZINCHENKO I.I., DOMBEK E., PIROGOV L.E., TOPCHIEVA A., JONCAS G., DEWANGAN L.K., OJHA D.K. and GHOSH S.K.
Abstract (from CDS):
The environment of S187, a nearby H II region (1.4 ± 0.3 kpc), is analyzed. A surrounding shell has been studied in the H I line, molecular lines, and also in infrared and radio continua. We report the first evidence of a clumpy H I environment in its photodissociation region. A background radio galaxy enables the estimation of the properties of cold atomic gas. The estimated atomic mass fraction of the shell is ∼260 M⊙, the median spin temperature is ∼50 K, the shell size is ∼4 pc with typical wall width around 0.2 pc. The atomic shell consists of ∼100 fragments. The fragment sizes correlate with mass with a power-law index of 2.39-2.50. The S187 shell has a complex kinematical structure, including the expanding quasi-spherical layer, molecular envelope, an atomic sub-bubble inside the shell and two dense cores (S187 SE and S187 NE) at different stages of evolution. The atomic sub-bubble inside the shell is young, contains a Class II young stellar object and OH maser in the centre and the associated YSOs in the walls of the bubble. S187 SE and S187 NE have similar masses (∼1200 and ∼900 M⊙, respectively). S187 SE is embedded into the atomic shell and has a number of associated objects, including high-mass protostars, outflows, maser sources, and other indicators of ongoing star formation. No YSOs inside S187 NE were detected, but indications of compression and heating by the H II region exist.
Abstract Copyright:
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society
Journal keyword(s):
stars: formation - ISM: bubbles - ISM: clouds - ISM: evolution - H ii regions - radio lines: ISM ;
Status at CDS
:
Examining the need for a new acronym.
Simbad objects:
15
Full paper
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