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

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 estim...

Full description

Saved in:
Bibliographic Details
Published in:Astronomy letters 2012-11, Vol.38 (11), p.721-730
Main Authors: Titarenko, A. R., Semenko, E. A., Ryabchikova, T. A.
Format: Article
Language:English
Subjects:
Astronomy
Astrophysics and Astroparticles
Atmosphere
Chemical composition
Chemical elements
Earth
Magnetic fields
Observations and Techniques
Physics
Physics and Astronomy
Stars & galaxies
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:1063-7737
1562-6873
DOI:10.1134/S1063773712110060