Are there S stars in galactic globular clusters

Two very red giant stars in NGC 6723 show enhanced ZrO bands. Comparison with 47 Tuc giants of similar near infrared colour shows that the TiO bands are abnormally weak, which accounts at least in part for the unusually red B-V and U-B as well as strong sodium D lines. Analogy with stars in the Magellanic Clouds suggests that the two NGC 6723 stars have mixed nuclear reaction products into the envelope. Their bolometric mag is Msub(bol) = -3.3, nearly one mag fainter than the faintest Magellanic Cloud star showing enhanced ZrO. Two red variables in 47 Tuc which have smaller ultraviolet deficiencies show no spectroscopic abnormalities, and a report of Ba II stars in M22 is shown to be unfounded. (author)