Do Hydrogen-deficient Carbon Stars have Winds?
  We present high resolution spectra of the five known hydrogen-deficient
carbon (HdC) stars in the vicinity of the 10830 Angstrom line of neutral
helium. In R Coronae Borealis (RCB) stars the He I line is known to be strong
and broad, often with a P Cygni profile, and must be formed in the powerful
winds of those stars. RCB stars have similar chemical abundances as HdC stars
and also share greatly enhanced 18O abundances with them, indicating a common
origin for these two classes of stars, which has been suggested to be white
dwarf mergers. A narrow He I absorption line may be present in the hotter HdC
stars, but no line is seen in the cooler stars, and no evidence for a wind is
found in any of them. The presence of wind lines in the RCB stars is strongly
correlated with dust formation episodes so the absence of wind lines in the HdC
stars, which do not make dust, is as expected.
