We present deep VIc CCD photometry for the open cluster 092-SC18 collected at the CTIO 1.5 meter telescope in April, 1994 as part of a program of photometric studies of old open clusters. VandenBerg (1985) isochrone fits to a V, V-I color-magnitude diagram yield estimates of cluster parameters of 4-6 Gyrs, with a range in metallicity of -0.23 to -0.75 dex. Based on the best fit isochrone, 092-SC18 is 5 Gyrs old, has an abundance of [Fe/H] = -0.45 dex, reddening of E(V-I) = 0.32, and (m-M)0 of 14.88 mag. With the current determination of the cluster's distance modulus, 092-SC18 is at a distance of 9.5 kpc, with a Galactocentric radius of 10.5 kpc, and lies 1.2 kpc below the Galactic plane. By extrapolating the main-sequence mass calculations to low-mass stars and accounting for a typical concentration of binaries, we place a lower limit to the cluster mass of ~ 4200 Msun. From an exponential fit to the stellar surface density of the cluster field, we find a linear diameter of 18 pc for 092-SC18.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1995