Abstract
In this work we compared the predictions about the tip-RGB bolometric luminosity of low-mass stars in stellar models built with the Cambridge-STARS code for stellar evolution, with the evidence provided by the observational data of 25 globular clusters from the largest homogeneous database in the NIR. We found that 12 well populated globular clusters (headed up by omega Centauri, the largest globular cluster in the galaxy) suggest mu_{nu}≤ 2.2× 10(-12}mu_{B) , while the uncertainties of both the stellar models and the observations require the more robust constraint mu_{nu}≤ 2.6× 10(-12}mu_{B) . Finally, using synthetic spectra constructed with the PHOENIX code for stellar atmospheres, we qualitatively estimated the effect on the brightness of specific NIR-bands.
