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 i lines are strong whereas neutron-capture elements are not enhanced. The isotopic 13CN(2, 0) lines relative to 12CN 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 04 to the west and 25 to the north from DY Per. This anonymous companion, with observed colour indices and , may be a foreground star.