On the Spectrum of Extremely Metal-Poor Star HD 52961

Abstract

Abstract High resolution spectra of the extremely metal-poor star HD 52961 are investigated. The atmospheric parameters found are: T eff = 6000 ± 100 K, log g = 0.5±0.5, ξ t = 6.8 km s−1, [Fe/H] = −4.50±0.20. The carbon abundance is close to the solar one, [C/H] = −0.17±0.12. At the same time abundances of heavy refractory elements are very low. The chemical composition and atmospheric parameters have not changed compared to the first observations of the star about 20 years ago, contrary to expectation of dissolving the peculiarities by mass-loss during a relatively short time. We also find evidence of ongoing mass-loss in this post-AGB star with a rate of Ṁ ≈ 5 · 10−6 M ⊙ yr−1.