uvbyCaHβ CCD Photometry of Clusters. VII. The Intermediate-Age Anticenter Cluster Melotte 71

CCD photometry on the intermediate-band uvbyCa H beta system is presented forthe anticenter, intermediate-age open cluster, Melotte 71. Restricting the datato probable single members of the cluster using the color-magnitude diagram andthe photometric indices alone generates a sample of 48 F dwarfs on theunevolved main sequence. The average E(b-y) = 0.148 +/- 0.003 (s.e.m.) orE(B-V) = 0.202 +/- 0.004 (s.e.m.), where the errors refer to internal errorsalone. With this reddening, [Fe/H] is derived from both m1 and hk, using H betaand b-y as the temperature index, with excellent agreement among the fourapproaches and a final weighted average of [Fe/H] = -0.17 +/- 0.02 (s.e.m.) forthe cluster, on a scale where the Hyades has [Fe/H] = +0.12. When adjusted forthe higher reddening estimate, the previous metallicity estimates fromWashington photometry and from spectroscopy are now in agreement with theintermediate-band result. From comparisons to isochrones of appropriatemetallicity, the cluster age and distance are determined as 0.9 +/- 0.1 Gyr and(m-M) = 12.2 +/- 0.1 or (m-M)_0 = 11.6 +/- 0.1. At this distance from the sun,Mel 71 has a galactocentric distance of 10.0 kpc on a scale where the sun is8.5 kpc from the galactic center. Based upon its age, distance, and elementalabundances, Mel 71 appears to be a less populous analog to NGC 3960.Comment: Accepted for Astronomical Journal. 38 page latex file includes 11 figures and short version of data table. Full table will appear in online AJ or may be requested from author