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Surface Compositions of RCRBs and Extreme Helium Stars - Some Connections Kameswar Rao Abstract Abundances of R Coronae Borealis stars and Extreme Helium (EHe) stars are discussed. Recent abundance estimates of the s-process elements in hot extreme helium stars show enhancements of lighter s-process elements (Y, Zr) relative to highier s-processes elements , a charactersic shared by R CrB stars. It also suggests that atleast some EHe stars went through an episode of s-process element synthesis in their earlier evolution. Majority of R CrB stars generally show high 12C/13C ratio in their atmospheres. Recent analysis of the spectrum of minority R CrB star V CrA however shows lower value between 4 - 10. The implications of these results is discussed. |