case western reserve university



Giants in the Local Region

Earle Luck (Case)

A spectroscopic analysis of 298 nearby giants will be discussed. Overall trends in the Z > 10 abundances are dominated by galactic chemical evolution while the light element abundances are influenced by stellar evolution as well as galactic evolution. We find several super-Li stars in our sample and confirm the mapping of Li abundances along the first-giant branch as being related to mixing depth. Once astration of lithium on the Main Sequence along with the overall range of Main Sequence lithium abundances are taken into account, the lithium abundances of the giants are not dramatically at odds with the predictions of standard stellar evolution. We find the giants to be carbon diluted in accord with standard stellar evolution and that the carbon and oxygen abundances determined for the local giants are consistent with those found in local field dwarfs. We find that there is evidence for systematic carbon variations in the red giant clump in the sense that the blue side of the clump is more carbon-poor (more diluted) than the red side.