New Optical and Infrared Photometric Study of Young Open Star Cluster NGC 7790

We present deep CCD photometry (V similar to 21 mag) in BVR Johnson-Cousin filters supported with 2MASS JHKs data set for the open star cluster NGC 7790. The cluster's parameters such as reddening, distance, metallicity and age etc horizontal ellipsis are derived using two color diagrams in optical and near-infrared bands. These parameters areE(B-V)= 0.512 +/- 0.006,EV-R= 0.382 +/- 0.005,EJ-H= 0.337 +/- 0.001 andE(J-Ks)= 0.505 +/- 0.001 mag, the distance modulus (m-M)(0)= 12.41 +/- 0.001 mag, which gives a distance of 3.035 kpc and the metallicityZ= 0.008. The age obtained by fitting the observed CMDs with Padova isochrones is 63.95 Myr. From the analysis of 2MASS data, the limiting radius of the cluster is found to be 9.7 +/- 0.83 arcmin, it reflects that the cluster is a compact cluster. The dynamical relaxation time of NGC 7790 is also determined and found to be 0.17 of its age, which means that the cluster is dynamically relaxed. Moreover, luminosity and mass functions are also investigated.