Mixed poloidal-toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn

Abstract

Previous studies of the chemically peculiar Bp star 36 Lyn revealed a moderately strong magnetic field, circumstellar material, and inhomogeneous surface abundance distributions of certain elements. We present in this paper an analysis of 33 high-signal-to-noise ratio, high-resolution Stokes IV observations of 36 Lyn obtained with the Narval spectropolarimeter at the Bernard Lyot telescope at Pic du Midi Observatory. From these data, we compute new measurements of the mean longitudinal magnetic field, Bl, using the multi-line least-squares deconvolution (LSD) technique. A rotationally phased Bl curve reveals a strong magnetic field, with indications for deviation from a pure dipole field. We derive magnetic maps and chemical abundance distributions from the LSD profiles, produced using the Zeeman Doppler Imaging code InversLSD. Using a spherical harmonic expansion to characterize the magnetic field, we find that the harmonic energy is concentrated predominantly in the dipole mode (l = 1), with significant contribution from both the poloidal and toroidal components. This toroidal field component is predicted theoretically, but not typically observed for Ap/Bp stars. Chemical abundance maps reveal a helium enhancement in a distinct region where the radial magnetic field is strong. Silicon enhancements are located in two regions, also where the radial field is stronger. Titanium and iron enhancements are slightly offset from the helium enhancements, and are located in areas where the radial field is weak, close to the magnetic equator.

arXiv comment12 pages, accepted for publication in MNRAS

References in corpus (24)

• Stable magnetic fields in stellar interiors
• Least squares deconvolution of the stellar intensity and polarization spectra
• Axisymmetric magnetic fields in stars: relative strengths of poloidal and toroidal components
• The MiMeS survey of magnetism in massive stars: Magnetic analysis of the O-type stars
• On the Stability of Non Force-Free Magnetic Equilibria in Stars
• Magnetic field topology of the unique chemically peculiar star CU Virginis
• Magnetic Doppler imaging of alpha^2 Canum Venaticorum in all four Stokes parameters. Unveiling the hidden complexity of stellar magnetic fields
• The extraordinary complex magnetic field of the helium-strong star HD 37776
• First Zeeman Doppler imaging of a cool star using all four Stokes parameters
• The stability of poloidal magnetic fields in rotating stars
• Stokes $IQUV$ Magnetic Doppler Imaging of Ap stars II: Next Generation Magnetic Doppler Imaging of ${\alpha }^2$ CVn
• Doppler imaging of chemical spots on magnetic Ap/Bp stars. Numerical tests and assessment of systematic errors
• Abundance distributions over the surfaces of magnetic ApBp stars: theoretical predictions
• Magnetic field topology and chemical abundance distributions of the young, rapidly rotating chemically peculiar star HR5624
• The surface magnetic field and chemical abundance distributions of the B2V helium-strong star HD184927
• Stokes $IQUV$ magnetic Doppler imaging of Ap stars - III. Next generation chemical abundance mapping of Alpha 2 CVn
• The magnetic field topology and chemical abundance distributions of the Ap star HD 32633
• Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712 II. Two-dimensional Magnetic Doppler Imaging in all four Stokes parameters
• Magnetic field topology of tau Sco. The uniqueness problem of Stokes V ZDI inversions
• Magnetic field topology and chemical spot distributions in the extreme Ap star HD 75049
• The magnetic Bp star 36 Lyncis, I. Magnetic and photospheric properties
• Magnetic Doppler imaging of the chemically peculiar star HD 125248
• Three-dimensional abundance distributions in ApBp star atmospheres: non-axisymmetric magnetic geometry
• The magnetic Bp star 36 Lyncis, II. A spectroscopic analysis of its co-rotating disk

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