  New photoelectric seven-color observations in the Vilnius system are
presented for 65 stars in the region of the open cluster NGC 752. Based on
individual stars with accurate photometric classifications, we determine the
apparent distance modulus (m-M)=8.38 and the mean reddening to the cluster
E(Y-V)=0.027, or E(B-V)=0.034. The mean photometric metallicity for the
main-sequence stars, [Fe/H]=-0.14, is found to be slightly lower than that
derived for the red clump giants, [Fe/H]=-0.08. This difference suggests that
red giants in later evolutionary phases may not have zero-age surface values of
[Fe/H]. We made use of the least-squares minimization techniques to fit the
Padova theoretical isochrones to the CMD, when the binary star population is
taken into account. By varying the distance modulus, metallicity and age, the
best match has been found between the seven magnitudes and colors of the
observed stars and those of model binaries, which gives the distance modulus by
0.2 mag smaller than that derived from individual stars, i.e., (m-M)=8.18, a
closely similar metallicity ([Fe/H]=-0.12), and age of 1.6 Gyr. With these
results, the fraction of photometric binaries among the main-sequence stars is
~40%.
