We present the first measure of Fe and Na abundances in NGC 6362 , a low-mass globular cluster where first and second generation stars are fully spatially mixed .
A total of 160 member stars ( along the red giant branch and the red horizontal branch ) have been observed with the multi-object spectrograph FLAMES at the Very Large Telescope .
We find that the cluster has an iron abundance of [ Fe/H ] =–1.09 \pm 0.01 dex , without evidence of intrinsic dispersion .
On the other hand , the [ Na/Fe ] distribution turns out to be intrinsically broad and bimodal .
The Na-poor and Na-rich stars populate , respectively , the bluest and the reddest red giant branches detected in the color-magnitude diagrams including the U filter .
The red giant branch is composed of a mixture of first and second generation stars in a similar proportion , while almost all the red horizontal branch stars belong to the first cluster generation .
Until now , NGC 6362 is the least massive globular cluster where both the photometric and spectroscopic signatures of multiple populations have been detected .