Do Hydrogen-deficient Carbon Stars have Winds?

Abstract

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.

18 pages incl. 3 figures; accepted by ApJ on 3 April 2009

References in corpus (3)

• Very Large Excesses of 18O in Hydrogen-Deficient Carbon and R Coronae Borealis Stars: Evidence for White Dwarf Mergers
• R Coronae Borealis stars in the Galactic Bulge discovered by EROS-2
• R Coronae Borealis at the 2003 Light Minimum

Cited by in corpus (5)

• Dust around R Coronae Borealis stars: I. Spitzer/IRS observations
• Variable Winds and Dust Formation in R Coronae Borealis Stars
• R Coronae Borealis and dustless Hydrogen-deficient Carbon stars have different oxygen isotope ratios
• High-resolution spectroscopy of the R Coronae Borealis and Other Hydrogen Deficient Stars
• Stars on the ascending helium giant branch I. From white dwarf merger to helium giant: the evolutionary state of the rapidly rotating hot subdwarf HE 1518-0948