DY Persei variables are a subclass of R Coronae Borealis variables. They are carbon-rich asymptotic giant branch stars that exhibit pulsational variability of AGB stars and irregular variability of RCB stars.
The star DY Persei is the prototype of this tiny class of variable stars.
Alcock, C. and Allsman, R.A. and Alves, D.R. and Axelrod, T.S. and Becker, A. and Bennett, D.P. and Clayton, G.C. and Cook, K.H. and Dalal, N. and Drake, A.J. and Freeman, K.C. and Geha, M. and Gordon, K.D. and Griest, K. and Kilkenny, D. and Lehner, M.J. and Marshall, S.L. and Minniti, D. and Misselt, K.A. and Nelson, C.A. and Peterson, B.A. and Popowski, P. and Pratt, M.R. and Quinn, P.J. and Stubbs, C.W. and Sutherland, W. and Tomaney, A. and Vandehei, T. and Welch, D.L., (June 2001). "The MACHO Project LMC Variable Star Inventory. X. The R Coronae Borealis Stars". Astrophysical Journal 554 (1): 298–315,. arXiv:astro-ph/0102262. Bibcode 2001ApJ...554..298A. doi:10.1086/321369.