Evolution of the Milky Way with radial motions of stars and gas

II. The evolution of abundance profiles from H to Ni

¹ Institut d’Astrophysique de Paris, UMR 7095 CNRS, Univ. P. & M. Curie, 98bis Bd Arago, 75104 Paris, France
e-mail: kubryk@iap.fr; prantzos@iap.fr
² Aix-Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
e-mail: lia@lam.fr

Received: 14 July 2014
Accepted: 1 May 2015

Abstract

Aims. We study the role of the radial motions of stars and gas on the evolution of abundance profiles in the Milky Way disk. We investigate, in a parametrized way, the impact of radial flows of gas and radial migration of stars induced mainly by the Galactic bar and its iteraction with the spiral arms.

Methods. We use a model with several new or up-dated ingredients (atomic and molecular gas phases, star formation depending on molecular gas, recent sets of metallicity-dependent stellar yields from H to Ni, observationally inferred SNIa rates), which reproduces most global and local observables of the Milky Way well.

Results. We obtain abundance profiles flattening both in the inner disk (because of radial flows) and in the outer disk (because of the adopted star formation law). The gas abundance profiles flatten with time, but the corresponding stellar profiles appear to be steeper for younger stars, because of radial migration. We find a correlation between the stellar abundance profiles and O/Fe, which is a proxy for stellar age. Our final abundance profiles are in overall agreement with observations, but slightly steeper (by 0.01−0.02 dex kpc^-1) for elements above S. We find an interesting “odd-even effect” in the behaviour of the abundance profiles (steeper slopes for odd elements) for all sets of stellar yields; however, this behaviour does not appear in observations, suggesting that the effect is, perhaps, overestimated in current stellar nucleosynthesis calculations.