W. J. Maciel -
Abstract #60
THE EVOLUTION OF RADIAL ABUNDANCE GRADIENTS IN THE GALAXY
C. Chiappini, W. J. Maciel
The formation of the Milky Way ed. E. Alfaro, A. J. Delgado, Cambridge, 171-172 (1995) One of the most important constraints of chemical evolution models (CEMs) of the Galaxy is the observed radial abundance gradients in the disk. To explain these gradients, different models have been proposed, and a large number of them are successful in accounting for the observed values, although they make use of very different assumptions. The investigations of the temporal behaviour of these metallicity gradients can contribute to clarify the problem of the non-uniqueness of CEMs for the Galaxy. As an example we have the opposite results obtained by the models of Tosi (this volume) and Ferrini et al. (1994). With a simplified chemical evolution model we investigate some of the fundamental processes responsible for the formation and evolution of the radial abundance gradients in the galactic disk. Preliminary numerical results for the radial variation of the metallicity at three different epochs show that these gradients depend both on time and position in the disk. They seem to be steeper in the inner regions than in the outer parts and tend to increase with time for galactocentric distances smaller than solar, being constant for greater distances.
