  DY Cen has shown a steady fading of its visual light by about 1 magnitude in
the last 40 years suggesting a secular increase in its effective temperature.
We have conducted non-LTE and LTE abundance analyses to determine the star's
effective temperature, surface gravity, and chemical composition using
high-resolution spectra obtained over two decades. The derived stellar
parameters for three epochs suggest that DY Cen has evolved at a constant
luminosity and has become hotter by about 5000 K in 23 years. We show that the
derived abundances remain unchanged for the three epochs. The derived
abundances of the key elements, including F and Ne, are as observed for the
extreme helium stars resulting from a merger of an He white dwarf with a C-O
white dwarf. Thus, DY Cen by chemical composition appears to be also a product
of a merger of two white dwarfs. This appearance seems to be at odds with the
recent suggestion that DY Cen is a single-lined spectroscopic binary.
