We present optical photometric and polarimetric observations of stars towards NGC 1931 with the aim to derive the cluster parameters such as distance , reddening , age and luminosity/mass function as well as to understand the dust properties and star formation in the region .
The distance to the cluster is found to be 2.3 \pm 0.3 kpc and the reddening E ( B - V ) in the region is found to be variable .
The stellar density contours reveal two clustering in the region .
The observations suggest differing reddening law within the cluster region .
Polarization efficiency of the dust grains towards the direction of the cluster is found to be less than that for the general diffuse interstellar medium ( ISM ) .
The slope of the mass function ( -0.98 \pm 0.22 ) in the southern region in the mass range 0.8 < M / M _ { \sun } \textless 9.8 is found to be shallower in comparison to that in the northern region ( -1.26 \pm 0.23 ) , which is comparable to the Salpeter value ( -1.35 ) .
The K-band luminosity function ( KLF ) of the region is found to be comparable to the average value of slope ( \sim 0.4 ) for young clusters obtained by , however , the slope of the KLF is steeper in the northern region as compared to the southern region .
The region is probably ionized by two B2 main-sequence type stars .
The mean age of the young stellar objects ( YSOs ) is found to be 2 \pm 1 Myr which suggests that the identified YSOs could be younger than the ionizing sources of the region .
The morphology of the region , the distribution of the YSOs as well as ages of the YSOs and ionizing sources indicate a triggered star formation in the region .