Vilnius Photometry and Reddening of the Young Open Cluster NGC 6913

Abstract

87 stars in the NGC 6913 field with both UBV and Vilnius photometry are selected to be the sample. The membership probability of the stars is greater than 50%. The correlation among Vilnius photometry, UBV photometry and reddening in the cluster is reviewed. It is found that the photometry in the Vilnius X, Y and Z bands can be used to make rough spectral classification. The values of E( B-V ) are well correlated with the Vilnius colors of X-Y, Y-Z, Z-V and V-S in NGC 6913. The ratio of ( V-S )/( Y-Z ) of the MPCM (Most Possible Cluster Members) is a constant (1.30 ∼ p0.06), and has no effect on the values of E( B-V ), ( B-V ) 0 and V 0 . Comparing with the observational data of all the stars of NGC 6913 region, we propose that the value of ( V-S )/( Y-Z ) can probably be used to select the preliminary candidates of one open cluster. In addition, 12 variable stars are discovered in the NGC 6913 region, in which star #155 has a variation with an amplitude of 4.25 mag.