Spectral analysis of DY Centauri, a hot R Coronae Borealis star with an unusually high hydrogen content.

Abstract

The photospheric parameters of DY Cen, an H-deficient early-B supergiant that is spectroscopically similar to the pulsating, extreme-He star BD-9 deg 4395, have been derived from high-resolution spectra via atomic data and line-blanketed model atmospheres. DY Cen is shown to be a metal-poor EHe star whose composition supports an anticorrelation between H and Fe abundances in EHe stars. Its previous evolution is reflected in its N-enriched atmospheric chemistry.