A multiwavelength investigation of the HII region S311: Young stellar
  population and star formation
  We present a multiwavelength investigation of the young stellar population
and star formation activities around the \hii region Sharpless 311. Using our
deep near-infrared observations and archival {\it Spitzer}-IRAC observations,
we have detected a total of 125 young stellar objects (YSOs) in an area of
$\sim$86 arcmin$^2$. The YSOs sample include 8 Class I and 117 Class II
candidate YSOs. The mass completeness of the identified YSOs sample is
estimated to be 1.0 \msun. The ages and masses of the majority of the candidate
YSOs are estimated to be in the range of $\sim$0.1$-$5 Myr and $\sim$0.3$-$6
\msun, respectively. The 8 \mum image of S311 displays an approximately
spherical cavity around the ionizing source which is possibly created due to
the expansion of the \hii region. The spatial distribution of the candidate
YSOs reveals that a significant number of them are distributed systematically
along the 8 $\mu$m emission with a majority clustered around the eastern border
of the \hii region. Four clumps/compact \hii regions are detected in the radio
continuum observations at 1280 MHz, which might have been formed during the
expansion of the \hii region. The estimated dynamical age of the region,
main-sequence lifetime of the ionizing source, the spatial distribution and
ages of the candidate YSOs indicate triggered star formation in the complex.
