dwarf Cepheids(AI Velorum stars) A group of pulsating variables that were classed as RR Lyrae stars but have been shown to have a lower luminosity in addition to a shorter period of about 1 to 5 hours. The variation in apparent magnitude (i.e. amplitude) ranges from 0.3 up to 1.2 but can be higher. At the lower amplitudes they are difficult to differentiate from Delta Scuti stars but are apparently older. Instabilities of period and light-curve shape are characteristic of these stars and many exhibit the Blazhko effect found in some RR Lyrae stars. The pulsations are probably mixtures of oscillations of a fundamental mode and those at higher harmonic frequencies (see pulsating variables).
dwarf Cepheids[′dwȯrf ′sef·ē·ədz]
A class of pulsating variable stars with periods of less than 6 hours and spectral type A or F; similar to δ Scuti stars but sometimes distinguished from them by the slightly larger amplitudes of their light curves. Also known as AI Velorum stars.