The high optical polarization in the Be/X-ray binary EXO 2030+375
arXiv:1409.8411 · doi:10.1093/mnras/stu2322
Abstract
Polarization in classical Be stars results from Thomson scattering of the unpolarized light from the Be star in the circumstellar disc. Theory and observations agree that the maximum degree of polarization from isolated Be stars is < 4%. We report on the first optical polarimetric observations of the Be/X-ray binary EXO\,2030+375. We find that the optical (R band) light is strongly linearly polarized with a degee of polarization of 19%, the highest ever measured either in a classical or Be/X-ray binary. We argue that the interstellar medium cannot account for this high polarization degree and that a substantial amount must be intrinsic to the source. We propose that it may result from the alignment of non-spherical ferromagnetic grains in the Be star disc due to the strong neutron star magnetic field.
arXiv commentto be published in MNRAS
References in corpus (13)
- Be/X-ray binaries
- Classical Be Stars: Rapidly Rotating B Stars with Viscous Keplerian Decretion Disks
- UBVRI Photometric Standard Stars Around the Celestial Equator: Updates and Additions
- NLTE Monte Carlo Radiative Transfer: I. The Thermal Properties of Keplerian Disks around Classical Be Stars
- Viscous Effects on the Interaction between the Coplanar Decretion Disc and the Neutron Star in Be/X-Ray Binaries
- Statistical Properties of Galactic Starlight Polarization
- Estimating Be Star Disk Radii using H-alpha Emission Equivalent Widths
- Non-LTE Monte Carlo Radiative Transfer: II. Non-Isothermal Solutions for Viscous Keplerian Disks
- A Decade in the Life of EXO 2030+375: A Multi-wavelength Study of an Accreting X-ray Pulsar
- Outbursts Large and Small from EXO 2030+375
- The RoboPol Pipeline and Control System
- Be Star Disk Models in Consistent Vertical Hydrostatic Equilibrium
- Recent RXTE/ASM and ROTSEIIId Observations of EXO 2030+375
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- Catalog of the Galactic population of X-ray pulsars in High-mass X-ray binary systems
- Identification of an X-ray Pulsar in the BeXRB system IGR J182191347
- Long-term optical variability of high-mass X-ray binaries. III. Polarimetry