Currently, mass-loss in the late Red Giant Branch (RGB) phase of low-mass
stars is still relatively poorly constrained by direct observations. Horizontal
Branch (HB) colour distributions can provide quantitative constraints to an
encounter-based mass-loss law, despite being indirect and model-dependent.
Recent infrared observations of dusty RGB stars in Globular Clusters (GCs)
suggest that mass-loss is episodic and weakly related to stellar properties.
Stellar encounters in GCs cores are a candidate mechanism for producing
RGB mass-loss with these characteristics, but a detailed quantitative
treatment of the effect is yet lacking. This would be particularly important in
GCs such as NGC 2808, where standard mass-loss prescriptions are unable
to fully predict the HB morphology, even when helium-enhanced
multipopulations are taken into account. I show that the maximum
temperature along the HB for a sample of GCs follows a characteristic
pattern with dynamical age (i.e. chronological age over relaxation time),
suggestive of the high-density state reached during core-collapse playing a
role in enhancing mass-stripping in the RGB phase. Moreover, simple,
analytical assumptions for the mass-loss law in stellar encounters naturally
result in a non-gaussian mass-loss distribution, with high skewness.
I compare it to Hubble Space Telescope (HST) data of HB-mass over a
sample of 71 GCs, and I briefly discuss the next step in modelling the
mass-loss interaction, i.e. smoothed-particle hydrodynamics simulations.