Small galaxies that are unusually blue. Thehave photometric colors of B-V = 0.0 to 0.30 mag, which is typical for relatively young stars of spectral type A. This suggests that BCDs are currently actively forming stars. These systems also have abundant interstellar gas (unlike other Elliptical galaxies).
Väikesed galaktikad, mis on ebatavaliselt sinist värvi. Nende fotovärvilisus B- V = 0, 0 kuni 0, 30 tähesuurust, mis on tüüpiline spektriklass A suhteliselt noortele tähtedele. See lubab oletada, et BCD- d on parajasti aktiivselt kujunevad tähed. Neil süsteemidel on ka hulganisti tähtedevahelist gaasi (erinevalt teistest elliptilistest galaktikatest).