  In atmospheres of magnetic main-sequence stars, the diffusion of chemical
elements leads to a number of observed anomalies, such as abundance spots
across the stellar surface. The aim of this study was to derive a detailed
picture of the surface abundance distribution of the magnetic chemically
peculiar star HD 3980. Based on high-resolution, phase-resolved spectroscopic
observations of the magnetic A-type star HD 3980, the inhomogeneous surface
distribution of 13 chemical elements (Li, O, Si, Ca, Cr, Mn, Fe, La, Ce, Pr,
Nd, Eu, and Gd) has been reconstructed. The INVERS12 code was used to invert
the rotational variability in line profiles to elemental surface distributions.
Assuming a centered, dominantly dipolar magnetic field configuration, we find
that Li, O, Mg, Pr, and Nd are mainly concentrated in the area of the magnetic
poles and depleted in the regions around the magnetic equator. The high
abundance spots of Si, La, Ce, Eu, and Gd are located between the magnetic
poles and the magnetic equator. Except for La, which is clearly depleted in the
area of the magnetic poles, no obvious correlation with the magnetic field has
been found for these elements otherwise. Ca, Cr, and Fe appear enhanced along
the rotational equator and the area around the magnetic poles. The intersection
between the magnetic and the rotational equator constitutes an exception,
especially for Ca and Cr, which are depleted in that region. No obvious
correlation between the theoretically predicted abundance patterns and those
determined in this study could be found. This can be attributed to a lack of
up-to-date theoretical models, especially for rare earth elements.
