A multiwavelength study of star formation in the vicinity of Galactic
  HII region Sh2-100
  We present multiwavelength investigation of morphology, physical-environment,
stellar contents and star formation activity in the vicinity of star-forming
region Sh 2-100. It is found that the Sh 2-100 region contains seven HII
regions of ultracompact and compact nature. The present estimation of distance
for three HII regions, along with the kinematic distance for others, suggests
that all of them belong to the same molecular cloud complex. Using NIR
photometry, we identified the most probable ionizing sources of six HII
regions. Their approximate photometric spectral type estimates suggest that
they are massive early-B to mid-O ZAMS stars and agree well with radio
continuum observations at 1280 MHz. The morphology of the complex shows a
non-uniform distribution of warm and hot dust, well mixed with the ionized gas,
which correlates well with the variation of average visual extinction (~ 4.2 -
97 mag) across the region. We estimated the physical parameters of ionized gas
with the help of radio continuum observations. We detected an optically visible
compact nebula located to the south of the 850 micron emission associated with
one of the HII regions and the diagnostic of the optical emission line ratios
gives electron density and electron temperature of ~ 0.67 x 10^3 cm^-3 and ~
10^4 K, respectively. The physical parameters suggest that all the HII regions
are in different stages of evolution, which correlate well with the probable
ages in the range ~ 0.01 - 2 Myr of the ionizing sources. The positions of IR
excess stars, ultracompact and compact HII regions at the periphery of an HI
shell, possibly created by a WR star, indicate that star formation in Sh 2-100
region might have been induced by an expanding HI shell.
