Analysis of the CN and CH molecular band strengths in stars of the open
  cluster NGC 6791
  Low resolution SDSS/SEGUE spectra have been used to study the behavior of the
strengths of the CN and CH molecular bands in stars at different evolutionary
stages of the open cluster NGC 6791. We find a significant spread in the
strengths of the CN bands, more than twice that expected from the
uncertainties, although the bimodalities observed in globular clusters are not
clearly observed here. This behavior, is observed not only among red clump
objects but also in unevolved stars such as those in the main sequence and
lower red giant branch. In contrast, not all the stars studied show significant
scatter in their CH strengths.
