IRAS two‐color diagram. Circles and triangles represent LSPVs and non‐LSPVs, respectively. The filled and open symbols refer to carbon‐ and oxygen‐rich objects, respectively. Crosses represent a sample of RCB stars (see text for details). Objects that have only an upper limit to the 60 μm flux are represented by a symbol with an arrow. Colors and regions in the diagram are those defined by Habing & van der Veen (1988). A blackbody line is shown, with temperatures indicated along it.