Abstract:
Young star clusters consisting of massive stars are the ideal sites to study the star formation
processes and influence of massive stars on the subsequent star formation. NGC 1893 is a young star cluster
associated with the HII region Sh2-236. It contains about five ‘O’-type stars and several early ‘B’-type stars.
It is located at a moderate distance of 3.25 kpc and has a reddening, EðB VÞ 0:4 mag. To characterize
the young low-mass stellar population in the central portion of the cluster, we carried out deep VI band
observations of the region using the 4K 4K CCD IMAGER mounted on the 3.6-m Devasthal Optical
Telescope. Our analysis shows that the present data are deep enough to detect stars below V 24 mag. We
found optical counterparts of 220 candidates, including young stars and unclassified cluster members from
Caramazza et al. (2008). We estimated the membership probabilities of the Gaia sources (mostly bright stars
with G\19 mag) located within the cluster radius using the Gaia EDR3. Toward the fainter end, we used the
optical color-magnitude diagram (CMD) to select the cluster members from a sample of young stars. The
locations of young stars on the CMD show that a majority of them are low-mass stars with age\10 Myr. The
unclassified candidates and X-ray sources from Caramazza et al. (2012) are also found to be young low-mass
stars. In total, we identified 425 young stars with age\10 Myr, and 110 of these are new. Most of these
stars appear as kinematic members of the cluster. By examining the CMD for the stars in the cluster region,
we suggest that the cluster has insignificant contamination due to field stars in the pre-main-sequence zone of
the CMD. The slope of the mass function in the mass range 0:2 M=M 2:5 is found to be
C ¼ 1:43 0:15, consistent with those of other star-forming complexes. The spatial distribution of the
young stars as a function of mass suggests that toward the cluster center, most of the stars are massive.
