Spectra of RV Tauri stars in the Large Magellanic Cloud

Low-resolution (0.6 nm) spectra of 24 RV Tauri stars in the LMC shows that most are of intermediate Preston type, hence intermediate metal deficiency. Two belong to Preston's class B, with enhanced CH and CN. Higher resolution spectra of the carbon star MACHO 47.2496.8 show that the C-12/C-13 ratio is high and that the Ball lines at 455.4 and 493.4 nm are enhanced. This suggests that the star has undergone the third dredge-up of helium-burning products on the thermally-pulsing AGB and is now in a post-AGB silage of evolution. JHK photometry from the 2MASS catalogue confirms and extends earlier findings that only moderate infrared excesses occur among this sample of RV Tauri stars.