Element identification in Przybylski's star

Cowley, Charles R.; Cowley, A. P.; Aikman, G. C. L.; Crosswhite, H. M.

doi:10.1086/155440

Cited by 26 publications

(30 citation statements)

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“…Figures 4-7, 9 and Tables 3, 4 are only available in electronic form at http://www.aanda.org (Wegner & Petford 1974;Cowley et al 1977;Cowley & Mathys 1998;Cowley et al 2000). For instance, in the latter study Cowley et al (2000) reported an overabundance by up to 4 dex (compared to the Sun) for elements heavier than Ni and enormously strong lines of the second ions of REEs compared to those of the first ions.…”

Section: Introductionmentioning

confidence: 97%

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Shulyak

Ryabchikova

Kildiyarova

et al. 2010

A&A

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Aims. Among the known Ap stars, HD 101065 is probably one of the most interesting objects, demonstrating very rich spectra of rareearth elements (REE). Strongly peculiar photometric parameters of this star can not be fully reproduced by any modern theoretical calculations, even those accounting for realistic chemistry of its atmosphere. In this study we investigate a role of missing REE line opacity and construct a self-consistent atmospheric model based on accurate abundance and chemical stratification analysis. Methods. We employed the LLmodels stellar model atmosphere code together with DDAFit and Synthmag software packages to derive homogeneous and stratified abundances for 52 chemical elements and to construct a self-consistent model of HD 101065 atmosphere. The opacity in REE lines is accounted for in details, by using up-to-date extensive theoretical calculations. Results. We show that REE elements play a key role in the radiative energy balance in the atmosphere of HD 101065, leading to the strong suppression of the Balmer jump and energy redistribution very different from that of normal stars. Introducing new line lists of REEs allowed us to reproduce, for the first time, spectral energy distribution of HD 101065 and achieve a better agreement between the unusually small observed Strömgren c 1 index and the model predictions. Using combined photometric and spectroscopic approaches and based on the iterative procedure of abundance and stratification analysis we find effective temperature of HD 101065 to be T eff = 6400 K.

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Section: Introductionmentioning

confidence: 97%

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Shulyak

Ryabchikova

Kildiyarova

et al. 2010

A&A

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“…HD 101065 does not show such variations. No changes in the appearance of spectral lines were discovered by the present author in coude spectra over the period from 1961 to 1974 and subsequently, Cowley et al (1977) 3 3 4 2 3 3 5 2 3 2 2 3 2 2 3 3 2 2 1 radial velocity during this period has remained practically constant. The spectral type B5 stated for HD 101065 in the Henry Draper Catalogue is certainly erroneous.…”

Section: Contributions 144mentioning

confidence: 42%

“…The evidence for the presence of lithium and strontium is subject to some doubt since these elements are represented only by one or two reasonably strong lines, which is insufficient for a positive identification in a spectrum as complex as that of HD 101065. The evidence for the presence of other elements is the subject of a critical examination in a recent paper by Cowley et al (1977). The effective temperature of the star is about 6100 K (Przybylski, 1977) which is substantially lower than the temperature of any known Ap star.…”

Section: Discussionmentioning

confidence: 99%

Search for Light Variations of HD 101065

Przybylski

1977

Publ. Astron. Soc. Aust.

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The eighth magnitude star HD 101065 is an extremely peculiar star with a unique spectrum characterized by numerous strong lines of the rare earths and the absence, or at least a remarkable weakening, of the lines of the iron group (Cowley et al. 1977). Besides the lanthanides only yttrium, zirconium, calcium and barium are definitely present in the atmosphere in substantial quantities. The evidence for the presence of lithium and strontium is subject to some doubt since these elements are represented only by one or two reasonably strong lines, which is insufficient for a positive identification in a spectrum as complex as that of HD 101065. The evidence for the presence of other elements is the subject of a critical examination in a recent paper by Cowley et al. (1977). The effective temperature of the star is about 6100 K (Przybylski, 1977) which is substantially lower than the temperature of any known Ap star. However, the effective temperature of HD 101065 is still subject to controversy (Wegner, 1976).

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“…HD 101065 does not show such variations. No changes in the appearance of spectral lines were discovered by the present author in coude spectra over the period from 1961 to 1974 and subsequently, Cowley et al (1977) radial velocity during this period has remained practically constant. The spectral type B5 stated for HD 101065 in the Henry Draper Catalogue is certainly erroneous.…”

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confidence: 42%

Two of the most Metal-deficient Stars

Bessel

1977

Publ. Astron. Soc. Aust.

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The metal content of stars (and galaxies) is of great interest as it relates to the theories of element formation, and through these to the history of our galaxy, the frequency of supernovae, the star formation rate and even the quasar rate. The kinematics and metallicity of stars have been correlated in a theory of formation of the galaxy by Eggen et al. (1962). Alternate theories (Unsold 1969) have also been proposed. Much work has gone into isolating individual metal deficient stars and determining their abundances, and also the abundances for stars in clusters.

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Element identification in Przybylski's star

Cited by 26 publications

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Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Realistic model atmosphere and revised abundances of the coolest Ap star HD 101065

Search for Light Variations of HD 101065

Two of the most Metal-deficient Stars

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