Vol. 537
In section 7. Stellar structure and evolution

The VLT/VISIR mid-IR view of 47 Tucanae. A further step in solving the puzzle of RGB mass loss

This article contributes to the ongoing controversy about the onset of dusty mass loss in stars on the first red giant branch (RGB). The mass loss phenomena in red giants are complicated and not fully reproduced by theoretical modeling. An analysis of Spitzer Space Telescope observations of globular clusters have found evidence of dusty mass loss in low-luminosity RGB stars. The authors of the present investigation used VLT/VISIR mid-IR imaging with much higher angular resolution than the Spitzer data. This overcomes a major problem of the Spitzer observations in the crowded fields of globular clusters. The new results do not find evidence of mass loss for low-luminosity RGB stars, only once the stars exceed a luminosity of 1000 times solar near the tip of the RGB dusty mass loss appears to set in.