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Speckle interferometry of magnetic stars

Russian version

    According to the current estimates, a few percent of Main Sequence B5-F5 stars reveal strong surface magnetic fields reaching the values of tens of kilogauss, which is an order of magnitude greater than the maximal magnetic field in sunspots. There are currently two dominating theories explaining the mechanism of generation of strong magnetic fields: the theory of a relic magnetic field and the dynamo theory. However, a lot of problems associated with the formation and evolution of magnetic stars do not find a full explanation within the currently available theories. This applies to the physical properties of magnetic stars, their multiplicity, the observed chemical composition anomalies, the effect of slow rotation of a number of magnetic stars and so on. An important direction in the study of magnetic stars is the study of binary and multiple systems with magnetic components using the techniques of spectroscopy and high angular resolution interferometry. A speckle interferometry program for studying the magnetic stars multiplicity is currently running at the BTA telescope. We have carried out interferometric observations of a sample 160 chemically peculiar Ap/Bp stars with proven global magnetic fields. Thirty-eight systems were resolved into individual components. Some systems (e.g., HD 5797, HD 144334, HD 213918) were detected for the first time. As an example, Figure 1 shows reconstructed images of two new binary systems with magnetic components. Given the published data on the spectroscopic and visual observations of the stars from the considered sample, we conclude that, contrary to the current views, the proportion of double and multiple magnetic stars does not differ from their non-magnetic counterparts.
Rastegaev D.A., Balega Yu.Yu., Dyachenko V.V., Maksimov A.F., Malogolovets E.V., Romanyuk I.I., Semenko E.A., Yakunin I.A.

Contact - Rastegaev D.A.

Fig.1. The images of the newly discovered on the BTA binary systems with magnetic components, reconstructed from bispectrum: HD 64486 (left panel), filter 800/100nm, Δm=3.43±0.02mag, ρ=0".350±0.002, <Be>=855±513G and HD 103498 (right panel), filter 800/100nm, Δm=1.81±0.02mag, ρ=0".138±0.001, <Be>=333±138G.