SIMBAD references

2014ApJ...793...76P - Astrophys. J., 793, 76 (2014/October-1)

On the binary helium star DY Centauri: chemical composition and evolutionary state.


Abstract (from CDS):

DY Cen has shown a steady fading of its visual light by about one magnitude in the last 40 yr, suggesting a secular increase in its effective temperature. We have conducted non-local thermodynamic equilibrium (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 yr. 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 a He white dwarf with a C-O white dwarf. Thus DY Cen by chemical composition appears to also be 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.

Abstract Copyright:

Journal keyword(s): stars: abundances - stars: atmospheres - stars: chemically peculiar - stars: evolution - stars: fundamental parameters - stars: individual: DY Cen

Simbad objects: 6

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