The Nature of RV Tauri Stars

Abstract

The infrared colours of the RV Tauri stars fall in a well-defined and thinly-populated region of the IRAS [12] – [25], [25] – [60] diagram. This provides an alternative method of searching for such stars. Stars with these IRAS colours as well as the K and L excesses which are also typical of RV Tauri stars have spectral types from B to M. The characteristic variability of RV Tauri-type has been found for several stars with spectral types typical of known RV Tauri stars, while stars of different spectral types do not vary in this way. RV Tauri stars are the stars with these colours, probably indicative of a dusty circumstellar disk, which lie within the Cepheid instability strip.