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| Paper: |
Did AGB Stars Leave Their Chemical Fingerprints in Galactic Globular Clusters? |
| Volume: |
378, Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes |
| Page: |
416 |
| Authors: |
Charbonnel, C. |
| Abstract: |
It has been known for more than two decades that globular cluster stars exhibit chemical abundance anomalies that are not shared by their field counterparts. Recent spectroscopic observations on very large telescopes have provided compelling evidence that these peculiar patterns were already present in the intra-cluster gas from which the stars observed today formed. A widely held hypothesis is that the gas was polluted early in the history of the globular clusters by material processed through hydrogen-burning at high temperature and then lost by stars more massive than the long-lived observed stars. This is the so-called self-enrichment scenario. However, the stellar sources responsible for these abundance variations have not been indubitably identified yet. It is often claimed that massive AGB stars may well be the polluters. Here we review the recent custom-made stellar models that were computed in order to test this hypothesis quantitatively, and we show that the AGB scenario encounters many difficulties. We discuss an alternative hypothesis which rests on pollution by rapidly rotating massive stars. |
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