Chemical composition and stratification of chemical elements in the atmosphere of the Ap star HD 8441

被引：6

作者：

Titarenko, A. R. ^{[1
,2
]}

Semenko, E. A. ^{[2
]}

Ryabchikova, T. A. ^{[3
]}

机构：

[1] Moscow MV Lomonosov State Univ, Fac Phys, Moscow 119991, Russia

[2] Russian Acad Sci, Special Astrophys Observ, Nizhnii Arkhyz 357147, Karachai Cherke, Russia

[3] Russian Acad Sci, Inst Astron, Moscow 119017, Russia

来源：

ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS | 2012年 / 38卷 / 11期

关键词：

stars-chemically peculiar stars; chemical composition; magnetic field; PECULIAR STARS; AM-STARS; ABUNDANCES; PHOTOMETRY; MULTIPLICITY; CATALOG; HD-8441; FIELD;

D O I：

10.1134/S1063773712110060

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We present the results of our abundance analysis for the atmosphere of the chemically peculiar Ap star HD 8441. HD 8441 is interesting in that the lines of rare-earth elements in its spectrum are weak and the longitudinal magnetic field component is small, being only several hundred gauss. Our estimates of the evolutionary status for HD 8441 have confirmed that it belongs to the group of Ap stars with weak lines of rare-earth elements in their spectra that leave the main sequence. A stratification analysis of the atmosphere of HD 8441 assuming a stepwise distribution of elements with depth reveals a nonuniform distribution of Si, Ca, Cr,Mn, and Fe with a significant increase in elemental abundances in deeper layers. The derived distribution qualitatively agrees with predictions of the theory of diffusive separation of elements under the action of radiation pressure forces and gravity. Comparison of the chemical composition and evolutionary status of HD 8441 with those of the stars HD 66318 and HD 144897 with strong magnetic fields shows that their atmospheres differ mainly by the abundances of rare-earth elements. The iron-peak elements exhibit large overabundances irrespective of the magnetic field strength.

引用

页码：721 / 730

页数：10

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