AAVSO/VSX beskriver skillnaden mellan typerna DYPer och RCB såhär.
DYPer:
Hydrogen-deficient stars that show unpredictable fading events but slower declines and roughly symmetric recoveries rather than the rapid decline and slow recovery observed in RCB stars. The amplitude of the declines is smaller than those of RCB stars.
Spectroscopically they seem to be normal C-type stars with evidence for C13 in their spectra, whereas one of the defining characteristics of RCB stars is the lack of this isotope of carbon.
At maximum they show semiregular behaviour with periods typical of SR stars and longer than the pulsations seen in RCB stars. They are also 10 times fainter on average.
Example: DY Per.
