| Subject | 
is part of | 
is an instance of | 
is a kind of | 
has definition | 
| AI Velorum star |   |   | dwarf Cepheid | A class of dwarf Cepheids. They are all RR Lyrae stars with periods shorter than 0.25 days. | 
| beat Cepheid |   |   | dwarf Cepheid | Dwarf Cepheid in which two or more almost identical periods exist which cause periodic amplitude fluctuations in their light curves. The "beat" period averages about 2 to 21/2 hours. | 
| SX Phoenicis | Phoenix | dwarf Cepheid |   | A dwarf Cepheid (spectral type A) with the shortest known period (1h19m). |