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 \pm 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 .