We present UBVRI photometry of 8702 stars in a 0.5 ^ { \circ } \times 0.5 ^ { \circ } field in the direction of NGC 7142 , taken with the Half Degree Imager ( HDI ) at the WIYN 0.9-meter telescope , to improve knowledge of this cluster ’ s basic parameters .
Our photometry spans the ranges 10.6 - 20.4 mag in U , 10.6 - 22.0 mag in B , 10.0 - 21.8 mag in V , 9.2 - 20.7 mag in R , and 8.5 - 19.9 mag in I .
Using color-color diagrams that employ all four color combinations that include U , versus B - V , we derive a reddening-metallicity relation for the cluster , with preferred values E ( B - V ) = 0.338 \pm 0.031 mag for the left-edge fiducial of the main sequence and [ Fe/H ] = 0.0 \pm 0.1 dex , where the Hyades cluster has been used as an unreddened reference cluster , the extinction relations of Cardelli have been employed , and the metallicity dependence of the Yonsei-Yale ( Y ^ { 2 } ) isochrones has been assumed .
Comparison of our data to the Y ^ { 2 } isochrones in multiple color-magnitude diagrams ( CMDs ) yields distance-metallicity and age-metallicity relations , with preferred values of m - M = 12.65 \pm 0.23 mag and age = 4.0 ^ { -0.7 } _ { +1.3 } Gyr .
Re-evaluation of the parameters of M67 using Stetson ’ s UBVI photometry yields [ Fe/H ] = -0.02 \pm 0.05 dex , E ( B - V ) = 0.04 \pm 0.01 mag , m - M = 9.75 \pm 0.03 mag , and age = 3.85 \pm 0.17 Gyr ; we thus find the metallicity and age of the two clusters to be indistinguishable .
A semi-independent analysis adopting the parameters of M67 and shifting the fiducials of the two clusters in six CMDs until they match strongly corroborates the values listed above .
The differences between our inferred parallaxes and the Gaia DR2 values are 87 \pm 60 \mu as for NGC 7142 and 48 \pm 15 \mu as for M67 , consistent with previous studies .