We have made an extensive survey of emission-line stars in the IC 1396 H ii region to investigate the low-mass population of pre-main sequence ( PMS ) stars .
A total of 639 H \alpha emission-line stars were detected in an area of 4.2 deg ^ { 2 } and their i ^ { \prime } -photometry was measured .
Their spatial distribution exhibits several aggregates near the elephant trunk globule ( Rim A ) and bright-rimmed clouds at the edge of the H ii region ( Rim B and SFO 37 , 38 , 39 , 41 ) , and near HD 206267 , which is the main exciting star of the H ii region .
Based on the extinction estimated from the near-infrared ( NIR ) color–color diagram , we have selected pre-main sequence star candidates associated with IC 1396 .
The age and mass were derived from the extinction corrected color-magnitude diagram and theoretical pre-main sequence tracks .
Most of our PMS candidates have ages of < 3 Myr and masses of 0.2–0.6 M _ { \sun } .
Although it appears that only a few stars were formed in the last 1 Myr in the east region of the exciting star , the age difference among subregions in our surveyed area is not clear from the statistical test .
Our results may suggest that massive stars were born after the continuous formation of low-mass stars for 10 Myr .
The birth of the exciting star could be the late stage of slow but contiguous star formation in the natal molecular cloud .
It may have triggered to form many low-mass stars at the dense inhomogeneity in and around the H ii region by a radiation-driven implosion .