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Title: Model of the expansion of H II region RCW 82

This paper aims to resolve the problem of formation of young objects observed in the RCW 82 H II region. In the framework of a classical trigger model the estimated time of fragmentation is larger than the estimated age of the H II region. Thus the young objects could not have formed during the dynamical evolution of the H II region. We propose a new model that helps resolve this problem. This model suggests that the H II region RCW 82 is embedded in a cloud of limited size that is denser than the surrounding interstellar medium. According to this model, when the ionization-shock front leaves the cloud it causes the formation of an accelerating dense gas shell. In the accelerated shell, the effects of the Rayleigh-Taylor (R-T) instability dominate and the characteristic time of the growth of perturbations with the observed magnitude of about 3 pc is 0.14 Myr, which is less than the estimated age of the H II region. The total time t {sub ∑}, which is the sum of the expansion time of the H II region to the edge of the cloud, the time of the R-T instability growth, and the free fall time, ismore » estimated as 0.44 < t {sub ∑} < 0.78 Myr. We conclude that the young objects in the H II region RCW 82 could be formed as a result of the R-T instability with subsequent fragmentation into large-scale condensations.« less
Authors:
;  [1] ;  [2]
  1. Lomonosov Moscow State University, Moscow 119991 (Russian Federation)
  2. Space Research Institute of RAS, Moscow 117997 (Russian Federation)
Publication Date:
OSTI Identifier:
22356970
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; DISTURBANCES; EVOLUTION; EXPANSION; FRAGMENTATION; GROWTH; HYDRODYNAMICS; INSTABILITY; LEAVES; PERTURBATION THEORY; SHELLS; STARS