Towards a better understanding of multiple populations in globular clusters
Abstract
Globular clusters (GCs) are self-graviting aggregates of hundreds of thousands of stars and count among the oldest structures of the Universe. Although they have long been considered as perfect laboratories for stellar physics, their dynamical and chemical evolution remain largely unknown. Moreover recent observations show that they are much more complex than originally thought. In individual GCs we observe some chemical features in long-lived low-mass stars on both the main sequence and the red giant branch; however in order to explain this features these stars have to reach very high temperatures in their interior which is not the case, thus they must have inherited their chemical properties when they were born from the intracluster medium. This implies that a first generation (1G) of massive and fast evolving stars has polluted the intracluster gas with H-burning products from their ejecta while a second generation (2G) of stars formed. The Gaia mission will help disentangling between the possible polluter scenario; indeed its high quality data will provide membership probabilities, distances, proper motions for the Milky Way GCs and thus will allow to better understand their formation and evolution.
- Publication:
-
SF2A-2013: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics
- Pub Date:
- November 2013
- Bibcode:
- 2013sf2a.conf..115C
- Keywords:
-
- globular cluster;
- multiple populations;
- horizontal branch;
- stars: evolution;
- stars: low-mass;
- stars: abundances