The extraordinary complex magnetic field of the helium-strong star HD 37776

Abstract

The early-type chemically peculiar stars often show strong magnetic fields on their surfaces. These magnetic topologies are organized on large scales and are believed to be close to an oblique dipole for most of the stars. In a striking exception to this general trend, the helium-strong star HD 37776 shows an extraordinary double-wave rotational modulation of the longitudinal magnetic field measurements, indicating a topologically complex and, possibly, record strong magnetic field. Here we present a new investigation of the magnetic field structure of HD 37776, using both simple geometrical interpretation of the longitudinal field curve and detailed modeling of the time-resolved circular polarization line profiles with the help of magnetic Doppler imaging technique. We derive a model of the magnetic field structure of HD 37776, which reconciles for the first time all magnetic observations available for this star. We find that the local surface field strength does not exceed ~30 kG, while the overall field topology of HD 37776 is dominated by a non-axisymmetric component and represents by far the most complex magnetic field configuration found among early-type stars.

9 pages, 8 figures; accepted for publication in The Astrophysical Journal

References in corpus (12)

• The surprising magnetic topology of tauSco: fossil remnant or dynamo output?
• Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
• Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: III. Angular Momentum Loss and Rotational Spindown
• On non-axisymmetric magnetic equilibria in stars
• The light variability of the helium strong star HD 37776 as a result of its inhomogeneous elemental surface distribution
• Discovery of 17 new sharp-lined Ap stars with magnetically resolved lines
• Magnetic fields and chemical peculiarities of the very young intermediate-mass binary system HD 72106
• Exploring the photometric signatures of magnetospheres around Helium-strong stars
• Fundamental Parameters of He-Weak and He-Strong Stars
• Recovery of the global magnetic field configuration of 78 Virginis from Stokes IQUV line profiles
• Remarkable non-dipolar magnetic field of the Bp star HD 137509
• Multicomponent radiatively driven stellar winds IV. On the helium decoupling in the wind of sigma Ori E

Cited by in corpus (55)

• A Magnetic Confinement vs. Rotation Classification of Massive-Star Magnetospheres
• A Universal Scaling for the Energetics of Relativistic Jets From Black Hole Systems
• The Magnetic Early B-type Stars III: A main sequence magnetic, rotational, and magnetospheric biography
• The Magnetic Early B-type Stars I: Magnetometry and Rotation
• A Volume Limited Survey of mCP Stars Within 100pc II: Rotational and Magnetic Properties
• Accretion, Outflows, and Winds of Magnetized Stars
• The eccentric massive binary V380 Cyg: revised orbital elements and interpretation of the intrinsic variability of the primary component
• The surface nitrogen abundance of a massive star in relation to its oscillations, rotation, and magnetic field
• HR 5907: Discovery of the most rapidly rotating magnetic B-type star by the MiMeS Collaboration
• MOBSTER -- VI. The crucial influence of rotation on the radio magnetospheres of hot stars
• The Magnetic Early B-type Stars IV: Breakout or Leakage? H$\alpha$ emission as a diagnostic of plasma transport in centrifugal magnetospheres
• Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal components
• Magnetic field topologies of the bright, weak-field Ap stars theta Aurigae and epsilon Ursae Majoris
• Surprising variations in the rotation of the chemically peculiar stars CU Virginis and V901 Orionis
• Doppler imaging of chemical spots on magnetic Ap/Bp stars. Numerical tests and assessment of systematic errors
• Critical evaluation of magnetic field detections reported for pulsating B-type stars in the light of ESPaDOnS, Narval and reanalyzed FORS1/2 observations
• Magnetic field topology and chemical abundance distributions of the young, rapidly rotating chemically peculiar star HR5624
• Evidence for radio and X-ray auroral emissions from the magnetic B-type star rho Oph A
• An Analysis of the Rapidly Rotating Bp Star HD 133880
• Three-dimensional magnetic and abundance mapping of the cool Ap star HD 24712 II. Two-dimensional Magnetic Doppler Imaging in all four Stokes parameters
• Two spotted and magnetic early B-type stars in the young open cluster NGC2264 discovered by MOST and ESPaDOnS
• Results of Magnetic Field Measurements Performed with the 6-m Telescope. IV. Observations in 2010
• Magnetic field topology and chemical spot distributions in the extreme Ap star HD 75049
• Monitoring and modelling of white dwarfs with extremely weak magnetic fields
• Gravity waves in strong magnetic fields
• Magnetic Fields of CP Stars in the OrionOB1 Association. IV. Stars of Subgroup 1b
• Mixed poloidal-toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn
• SDSS-V Local Volume Mapper (LVM): A Glimpse into Orion
• The accelerating rotation of the magnetic He-weak star HD 142990
• Low-amplitude rotational modulation rather than pulsations in the CoRoT B-type supergiant HD 46769
• Magnetic Doppler imaging considering atmospheric structure modifications due to local abundances: a luxury or a necessity?
• BD-19 5044L: discovery of a short-period SB2 system with a magnetic Bp primary in the open cluster IC 4725
• Diagnostic of stellar magnetic fields with cumulative circular polarisation profiles
• Magnetic Field and Atmospheric Chemical Abundances of the Magnetic Ap Star HD 318107
• Torsional oscillations and observed rotational period variations in early-type stars
• Asteroseismic constraints on active latitudes of solar-type stars: HD173701 has active bands at higher latitudes than the Sun
• B fields in OB stars (BOB): Detection of a strong magnetic field in the O9.7 V star HD54879
• Effect of a magnetic field on massive star winds I: mass-loss and velocity for a dipole field
• The complex fossil magnetic field of the $\delta$ Scuti star HD\,41641
• Linking the Interiors and Surfaces of Magnetic Stars
• The magnetic field and magnetosphere of Plaskett's star: A fundamental shift in our understanding of the system
• Magnetic field geometry and chemical abundance distribution of the He-strong star CPD -57 3509
• Confirmation of xi^1 CMa's ultra-slow rotation: magnetic polarity reversal and a dramatic change in magnetospheric UV emission lines
• Electron Scattering Emission in the Light Curves of Stars with Centrifugal Magnetospheres
• Magnetic properties of three cool CP stars with strong fields
• Photometric signatures of corotating magnetospheres of hot stars governed by higher-order magnetic multipoles
• Standing torsional Alfvén waves as the source of the rotational period variation in magnetic early-type stars
• Extremely asymmetric bipolar magnetic field of the Bp star HD 57372
• Secular dipole-dipole stability of magnetic binaries
• MOBSTER -- VII. Using light curves to infer magnetic and rotational properties of stars with centrifugal magnetospheres
• Horizontal flows in the atmospheres of chemically peculiar stars
• Spectropolarimetry of Magnetic Chemically Peculiar Stars in the Orion OB1 Association
• Stellar Magnetism
• Radio Spectral Energy Distributions for Single Massive Star Winds with Free-Free and Synchrotron Emission
• Spectropolarimetry of massive stars: Requirements and potential from today to 2030