Terzan 8: a Sagittarius-flavoured globular cluster
  Massive globular clusters (GCs) contain at least two generations of stars
with slightly different ages and clearly distinct light elements abundances.
The Na-O anticorrelation is the best studied chemical signature of multiple
stellar generations. Low-mass clusters appear instead to be usually chemically
homogeneous. We are investigating low-mass GCs to understand what is the lower
mass limit where multiple populations can form, mainly using the Na and O
abundance distribution. We used VLT/FLAMES spectra of giants in the low-mass,
metal-poor GC Terzan 8, belonging to the Sagittarius dwarf galaxy, to determine
abundances of Fe, O, Na, alpha-, Fe-peak, and neutron-capture elements in six
stars observed with UVES and 14 observed with GIRAFFE. The average metallicity
is [Fe/H]=-2.27+/-0.03 (rms=0.08), based on the six high-resolution UVES
spectra. Only one star, observed with GIRAFFE, shows an enhanced abundance of
Na and we tentatively assign it to the second generation. In this cluster, at
variance with what happens in more massive GCs, the second generation seems to
represent at most a small minority fraction. We discuss the implications of our
findings, comparing Terzan 8 with the other Sgr dSph GCs, to GCs and field
stars in the Large Magellanic Cloud, Fornax, and in other dwarfs galaxies.
