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Paper: The Non-uniform Surface Chromium Distribution of 78 Vir
Volume: 362, The Seventh Pacific Rim Conference on Stellar Astrophysics
Page: 258
Authors: Khalack, V.R.; Wade, G.A.; Mkrtichian, D.E.
Abstract: The surface magnetic field configuration of the Ap star 78 Vir is reconstructed in the framework of the magnetic charge description (MCD) method from the analysis of Stokes IQUV spectra. Magnetically-sensitive Cr I and Cr II lines are analysed by assuming a stellar atmosphere model with Teff=9250K, log(g)=4.5 and by postulating a non-uniform surface chromium distribution. We show that the global magnetic field structure determined using Cr lines can be well-described by a slightly decentered magnetic dipole model, which provides the best fit to the majority of lines analysed at the level of χ2 = 2.77÷4.76. An acceptable fit to the Cr line profiles requires the introduction of a non-uniform surface distribution of this element, which appears to show an enhanced abundance in the vicinity of the negative magnetic pole.
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