EAS Publications Series
Volume 67-68, 2014The Milky Way Unravelled by Gaia: GREAT Science from the Gaia Data Releases
|Page(s)||33 - 39|
|Section||The Physics and Science Promise of Gaia|
|Published online||17 July 2015|
N.A. Walton, F. Figueras, L. Balaguer-Núñez and C. Soubiran (eds)
EAS Publications Series, 67–68 (2014) 33-39
How robust are our views of Milky Way stellar populations before Gaia?
GEPI, Observatoire de Paris, CNRS, Université Paris Diderot, 5 place Jules Janssen, 92190 Meudon, France
One year before the first release of the first data from Gaia, how robust are our views of the Milky Way stellar populations? Recent results have shown that limits, differences and/or continuities between populations are not where we thought they were just a few years ago. The outer disk (> 10kpc) has properties essentially different from the inner (thin+thick) disk, while the bulge is best explained in terms of disk populations, with a negligible or inexistent classical bulge, suggesting that the Milky Way is a pure disk galaxy. Much less contingent than previously envisaged, the thick disk is probably the main phase of stellar mass creation in the MW, and the parent population of the thin disk. These results lead to fundamental changes in our views on the stellar mass growth of the Galaxy, secular mass redistribution in the disk, and imply a change of paradigm of the chemical evolution. I review these different advances, and discuss some of the key questions.
© EAS, EDP Sciences, 2015