Testing Triggered Star Formation in Six H II Regions
  We investigated six H II regions with infrared, bright rimmed bubble or
cometary morphology, in search of quantitative evidence for triggered star
formation, both collect and collapse and radiatively driven implosion. We
identified and classified 458 Young Stellar Objects (YSOs) in and around the H
II regions. YSOs were determined by fitting a collection of radiative transfer
model spectral energy distributions (SEDs) to infrared photometry for a large
sample of point sources. We determined areas where there exist enhanced
populations of relatively unevolved YSOs on the bright rims of these regions,
suggesting that star formation has been triggered there. We further
investigated the physical properties of the regions by using radio continuum
emission as a proxy for ionizing flux powering the H II regions, and 13CO (1-0)
observations to measure masses and gravitational stability of molecular clumps.
We used an analytical model of collect and collapse triggered star formation,
as well as a simulation of radiatively driven implosion, and thus we compare
the observed properties of the molecular gas with those predicted in the
triggering scenarios. Notably, those regions in our sample that show evidence
of cometary, or "blister," morphology are more likely to show evidence of
triggering.
  Keywords: HII regions -- ISM: bubbles -- Stars: formation -- Stars:
protostars
