No Heavy-Element Dispersion in the Globular Cluster M92
Although there have been recent claims that there is a large dispersion in the abundances of the heavy neutron capture elements in the old Galactic globular cluster M92, we show that the measured dispersion for the absolute abundances of four of the rare earth elements within a sample of 12 luminous red giants in M92 (≤0.07 dex) does not exceed the relevant sources of uncertainty. As expected from previous studies, the heavy elements show the signature of the r-process. Their abundance ratios are essentially identical to those of M30, another nearby globular cluster of similar metallicity.
Additional Information© 2011 The American Astronomical Society. Received 2011 July 9; accepted 2011 September 12; published 2011 September 27. Based in part on observations obtained at the W.M. Keck Observatory, which is operated jointly by the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. We are grateful to the many people who have worked to make the Keck Telescope and its instruments a reality and to operate and maintain the Keck Observatory. The author wishes to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, none of the observations presented herein would have been possible. The author thanks NSF Grant AST-0908139 for partial support.
Published - Cohen2011p16405Astrophys_J_Lett.pdf
Accepted Version - 1109.2876.pdf