SIMBAD references

Through the analysis of galactic globular clusters data we show that the integrated Hβ index is well represented by a bivariate function of metallicity and a parameter describing the horizontal branch morphology. The present results indicate that blue horizontal branch and blue tail stars may give a substantial contribution to the Hβ strength. Metallicity indices were synthesized using observed stellar populations in clusters, in order to provide a quantitative estimate of such a contribution.