W. J. Maciel -
Abstract #109
DYNAMICAL EVIDENCE OF THE AGE-METALLICITY RELATION IN THE MILKY WAY DISK
H. J. Rocha-Pinto, R. H. O. Rangel, G. F. Porto de Mello, G. A. Bragança, W. J. Maciel
Astron. Astrophys. 487, L9-L12 (2006)
Aims: We studied the relationship between the average stellar abundance of several
elements and the orbital evolution of stars in the neighbourhood of the Sun.
Methods: We used both observational data for 325 late-type dwarfs in a volume-complete
sample and simulations of the orbital diffusion Metallicities, ages, and initial
position and velocities for the simulated stars are sampled from empirical distributions
of these quantities in the Milky Way.
Results: We found that that there is a relationship between the average stellar
abundance of Fe, Na, Si, Ca, Ni, and Ba and the mean orbital radius of stars
currently passing through the solar neighbourhood The greater the difference between
the mean orbital radius and the solar Galactocentric distance, the more deficient the
star is, on average, in these chemical species.
Conclusions: The stars that take a longer time to come from their birthplaces to
arrive in the present solar neighbourhood are more likely to be more metal-poor
than those that were born here. This result is a direct, independent indication
that a tightly defined Galactic age-metallicity relation exists.
