The cool Galactic R Coronae Borealis variable DY Persei

Abstract

Results of first CCD photometry during the recent deep light decline, and high-resolution spectroscopy, are presented for DY Persei. The spectra show variable blueshifted features in the sodium D lines. The C  lines are strong whereas neutron- capture elements are not enhanced. The isotopic 13 CN(2, 0) lines relative to 12 CN are of similar strength with those for the carbon star U Hya. All these confirm the RCB nature of DY Per and the existence of ejected clouds. At least two clouds are revealed at −197.3 and −143.0 km s −1 . A star was detected about 0. 4t o the west and 2 . 5 to the north from DY Per. This anonymous companion, with observed colour indices (B − V) = 0.68 and (V − R) � 1.1, may be a foreground star.