The K-dwarf problem and the time-dependence of gaseous accretion to the Galactic disc

¹ Instituto de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
² Consejo Superior de Investigaciones Científicas, Spain e-mail: jeb@ll.iac.es

Corresponding author: E. Casuso, eca@ll.iac.es

Received: 24 September 2003
Accepted: 19 February 2004

Abstract

In this article we compare and contrast the predictions of models we have published previously, with the most recent observational data on the G-dwarf/K-dwarf metallicity distribution in the local Galaxy, as well as with up to date plots showing the relation between the Be and B abundances of local stars and their Fe abundances. We show how the data clearly support models in which infall to the plane has not declined secularly during the disc lifetime, and that the best fits are to models in which the accretion rate has tended to a slow increase. These models, devised to give the best possible account of the G-dwarf metallicity distribution, turn out to give an even better account of the K-dwarf distribution. They also do surprisingly well at predicting the observed plots of Be and B vs. Fe in the disc.