No evidence for multiple stellar populations in the low-mass Galactic
  globular cluster E 3
  Multiple stellar populations are a widespread phenomenon among Galactic
globular clusters. Even though the origin of the enriched material from which
new generations of stars are produced remains unclear, it is likely that
self-enrichment will be feasible only in clusters massive enough to retain this
enriched material. We searched for multiple populations in the low mass (M~1.4
x 10^4 M_sun) globular cluster E 3, analyzing SOAR/Goodman multi-object
spectroscopy centered on the blue CN absorption features of 23 red giant branch
stars. We find that the CN abundance does not present the typical bimodal
behavior seen in clusters hosting multi stellar populations, but rather a
unimodal distribution that indicates the presence of a genuine single stellar
population, or a level of enrichment much lower than in clusters that show
evidence for two populations from high-resolution spectroscopy. E 3 would be
the first bona fide Galactic old globular cluster where no sign of
self-enrichment is found.
