A multi-wavelength study of star formation around HII regions.

摘要

The environment of high mass star formation is turbulent and complex. New stars are continually forming while the HII region, stellar winds, and supernovae of the current generation of massive stars destroy the parent molecular cloud. One of the more interesting premises connected with high mass star formation is the possibility that one generation of massive stars and its associated HII region could trigger further star formation as the HII region expands into the surrounding interstellar medium.; This thesis uses the Canadian Galactic Plane Survey (a multi-wavelength survey of a portion of the outer Galactic plane) and other archived survey data to study star formation around HII regions, with a particular emphasis on the identification and analysis of evidence for triggered star formation. The use of multi-wavelength data is essential to investigate the ionised, neutral, and molecular components of the gas, the dust, and the population of young stellar objects (YSOs). The survey nature of the data is exploited to study multiple HII regions and star formation in different environments (from energetic to quiescent) in a uniform manner.; A variety of HII regions have been explored: W5 and W3/W4, large bright HII regions in the Perseus Arm; W1, a bright HII region in the local arm; LBN 140.77 -1.42, LBN 139.57 +2.70, and LBN 140.07 +1.64, a series of faint HII regions in the Perseus Arm; Sh 2-183, Sh 2-170, Sh 2-173, smaller HII regions at distances of order 2.2 kpc; and Sh 2-185, a nearby HII region. Evidence for direct interactions between the YSOs and molecular gas and the HII region have been found on large and small scales. The interaction between components of the ISM and the distribution and luminosity of star formation has been analysed. Time scales for star formation and triggering have been calculated where possible and the plausibility of triggering evaluated. The nature of star formation outside the neighbourhood of the HII region has been explored and compared with the more active regions.; Properties of star formation and molecular clumps in different regions over the sample have been studied, including the areal density of star formation, molecular clump parameters, and the size-linewidth relation.