Deep optical survey of the stellar content of Sh2-311 region
  The stellar content in and around Sh2-311 region have been studied using the
deep optical observations as well as near-infrared (NIR) data from 2MASS. The
region contains three clusters, viz. NGC 2467, Haffner 18 and Haffner 19. We
have made an attempt to distinguish the stellar content of these individual
regions as well as to re-determine their fundamental parameters such as
distance, reddening, age, onto the basis of a new and more extended optical and
infrared photometric data set. NGC 2467 and Haffner 19 are found to be located
in the Perseus arm at the distances of 5.0 $\pm$ 0.4 kpc and 5.7 $\pm$ 0.4 kpc,
respectively, whereas Haffner 18 is located at the distance of 11.2 $\pm$ 1.0
kpc. The clusters NGC 2467 and Haffner 19 might have formed from the same
molecular cloud, whereas the cluster Haffner 18 is located in the outer
galactic arm, i.e. the Norma-Cygnus arm. We identify 8 class II young stellar
objects (YSOs) using the NIR $(J - H)/(H - K)$ two colour diagram. We have
estimated the age and mass of the YSOs identified in the present work and those
by Snider et al. (2009) using the $V/(V - I)$ colour-magnitude diagram. The
estimated ages and mass range of the majority of the YSOs are $\lesssim$1 Myr
and $\sim$0.4 - 3.5 \msun, respectively, indicating that these sources could be
T-Tauri stars or their siblings. Spatial distribution of the YSOs shows that
some of the YSOs are distributed around the H II region Sh2-311, suggesting a
triggered star formation at its periphery.
