3D distribution models of Ca, Cr, and Fe in a magnetic CP star atmosphere with anisotropic wind

G. Alecian (1) , M. J. Stift

1 LUTH (UMR_8102) - Laboratoire Univers et Théories

We present time-dependent atomic diffusion calculations for Ca, Cr, and Fe in a stellar magnetic atmosphere including an anisotropic wind. For three different models of mass-loss rates (or wind), we obtain a 3D description of the entire atmosphere. In two of these models, the mass-loss rate varies according to the magnetic field inclination, the assumed field geometry being non-axisymmetric. When the dipolar component of the magnetic field dominates, we find that ring-like abundance structures will be prominent. Spot-like distributions can also exist according to the field geometry. Abundance distributions turn out to be highly sensitive to the mass-loss model. The results are discussed and compared to an observational model of a real chemically peculiar star (θ Aurigae) that features parameters close to those of the model we have adopted for our calculations.

Keywords: diffusion; magnetic fields; stars: abundances; stars: chemically peculiar; stars: mass-loss

Domains: Sciences of the Universe [physics]

G. Alecian, M. J. Stift. 3D distribution models of Ca, Cr, and Fe in a magnetic CP star atmosphere with anisotropic wind. Monthly Notices of the Royal Astronomical Society, 2021, 504, pp.1370-1378. ⟨10.1093/mnras/stab952⟩. ⟨insu-03713217⟩