The Chemical Composition of Very-Strong Lined Giants
Session 12 -- Stars and Variable Stars
Oral presentation, Monday, June 12, 1995, 10:00am - 11:30am

## [12.02] The Chemical Composition of Very-Strong Lined Giants

R. Earle Luck and Sharon L. Challener (Case Western Reserve University and Allegheny College)

Stellar parameters and abundances for a sample of 55 G/K field giants of which 22 are normal stars and the other 33 are classified as VSL have been determined based on high-resolution - high signal-to-noise KPNO coude spectra. The primary pertinent points of comparison between these stars are 1) VSL stars have [Fe/H] ratios that average +0.1 dex relative to normal giants; 2) VSL stars are modestly carbon and nitrogen rich relative to the normal stars. The mean difference in [C/Fe] is +0.1 and for [N/Fe] is +0.05; 3) The [O/Fe] ratios of the normal and VSL stars are comparable; and 4) The lithium abundances, $$^{12}$$C/$$^{13}$$C ratios, and [M/Fe] ratios for Z $\rm >$ 10 are comparable in the two groups. The combination of the first through third points is sufficient to explain the difference in VSL and normal G/K giant spectra.

Our preferred interpretation of the VSL stars is that they are the result of normal evolution of a dwarf whose initial composition is somewhat metal- and carbon-rich. The fraction of stars with these properties is consistent with the number of VSL giants.