Lithium abundances in globular clusters
  Lithium is created during the Big Bang nucleosynthesis and it is destroyed in
stellar interiors at relatively low temperatures. However, it should be
preserved in the stellar envelopes of unevolved stars and progressively diluted
during mixing processes. In particular, after the first dredge-up along the
RGB, lithium should be completely destroyed, but this is not what we observe
today in globular clusters. This element allows to test stellar evolutionary
models, as well as different types of polluters for second population stars in
the multiple population scenarios. Due to the difficulty in the measurement of
the small available lithium line, few GCs have been studied in details so far.
Literature results are not homogeneous for what concerns type of stars, sample
sizes, and chemical analysis methods. The Gaia-ESO survey allows us to study
the largest sample of GCs stars (about 2000, both dwarfs and giants) for which
the lithium has been analysed homogeneously.
