Lanthanides and other spectral oddities in a Centauri (Research Note) Ce III, Nd III, Kr II, and broad absorption features

作者：Cowley C R^*; Hubrig S; Gonzalez J F

来源：Astronomy & Astrophysics, 2010, 523: A82.

DOI：10.1051/0004-6361/201015492

• stars: chemically peculiar
• stars: variable: general
• stars: individual: a Cen

Context. There is considerable interest in the helium variable a Cen as a bridge between helium-weak and helium-strong CP stars.
Aims. We investigate Ce III and other possible lanthanides in the spectrum the of hottest chemically peculiar (CP) star in which these elements have been found. A Kr II line appears within a broad absorption which we suggest may be due to a high-level transition in C II.
Methods. Wavelengths and equivalent widths are measured on high-resolution UVES spectra, analyzed, and their phase-variations investigated.
Results. New, robust identifications of Ce III and Kr II are demonstrated. Nd III is likely present. A broad absorption near lambda 4619 is present at all phases of a Cen, and in some other early B stars.
Conclusions. The presence of lanthanides in a Cen strengthens the view that this star is a significant link between the cooler CP stars and the hotter helium-peculiar stars. Broad absorptions in a Cen are not well explained.

• 出版日期2010-12