Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712: III. Three-dimensional abundance distribution of iron and calcium
2016 (English)In: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746Article in journal (Other academic) Submitted
Context. The presence of abundance inhomogeneities in the atmospheres of chemically peculiar Ap stars presents us with an outstand- ing opportunity to investigate three-dimensional abundance distributions of chemical elements with Doppler imaging techniques, and confront these observations with the theory of atomic diffusion in the presence of a magnetic field. Aims. In this paper we present the first three-dimensional abundance distribution of Fe and Ca in the atmosphere of the cool, magnetic, chemically peculiar star HD 24712.
Methods. We used a modified version of the magnetic Doppler imaging code invers10 to derive the abundance distribution of Fe and Ca in three directions in a self-consistent way without any simplifying assumptions about the magnetic field structure of HD 24712. The analysis was performed on the basis of phase-resolved observations obtained with the HARPSpol instrument at the 3.6 m ESO telescope.
Results. The resulting three-dimensional abundance distributions of Fe and Ca successfully reproduce the observed line profiles of all spectral lines used in the inversion. We reveal a strong correlation between the horizontal and vertical abundance distribution of Fe derived from two and three-dimensional magnetic Doppler imaging, higher effective local abundance corresponds to the stratification profiles in which the transition region is shifted higher in the atmosphere. However, we could not confirm the presence of a similar correlation for Ca.
Place, publisher, year, edition, pages
chemically peculiar stars, stellar atmospheres, abundances, HD 24712, magnetic field
Astronomy, Astrophysics and Cosmology
Research subject Astronomy
IdentifiersURN: urn:nbn:se:uu:diva-278534OAI: oai:DiVA.org:uu-278534DiVA: diva2:906627