The old open cluster Trumpler 5 and the chemical evolution of the galactic disc

We present CCD VIKC and Washington CT1 photometry in the field of Trumpler 5. From the comparison of the cluster CMDs with theoretical isochrones, the Standard Giant Branches method and measures of deltaV and deltaT1, we derive reddening, distance, age and metallicity. We examined the overall properties of all clusters with ages of 3 Gyr or older. No evidence either for an abundance Z gradient or for an age-metallicity relation is found. We suggest that the Galactic disc might have been formed inside-out and that the relative lack of very old clusters with Z > 0.5 kpc would be reflecting the transition between the formation of the globular and open cluster systems.Fil: Piatti, Andres Eduardo. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Claria Olmedo, Juan Jose. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ahumada, Andrea Veronica. Universidad Nacional de Cordoba. Observatorio Astronomico de Cordoba; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin