COLOR GRADIENTS IN 4 KING-TYPE GLOBULAR-CLUSTERS - NGC-2298, NGC-6402, NGC-6934, AND NGC-7089

We present CCD surface photometry for four globular clusters: NGC 2298 , NGC 6402, NGC 6934 and NGC 7089. Our photometry was aimed at the cen tral similar to 3 arcmin region in each cluster. We show that the surf ace brightness distributions of these clusters are well described by t he isothermal King (1966) models. Our color analysis shows that NGC 70 89 exhibits a remarkable color gradient in which the central region is bluer than the outer parts by the amplitude in B - V similar to 0.1 m ag/square ''. Color gradients have also been detected in the central r egions of NGC 6402 and NGC 6934, although the variation does not exten d to outer part. No gradient has been detected in NGC 2298. Similar co lor gradients have been previsouly observed exclusively in highly conc entrated systems classified as post core collapse clusters.