Evolved stars with initial mass between 8-10 and 40 Mo. They are core-helium burning. Their spectral type is K/M, their luminosity type is I. They are losing mass and thus can be strong infrared emitters due to circumstellar dust. They are pulsating, though often irregularly on a very long time scale (a few years, Lc variables according to the GCVS classification).

-- CecileLoup - 2014-02-20