Polarization due to rotational distortion in the bright star Regulus

@article{Cotton2017PolarizationDT,
  title={Polarization due to rotational distortion in the bright star Regulus},
  author={Daniel V. Cotton and Jeremy Bailey and Ian D. Howarth and Kimberly Bott and Lucyna Kedziora-Chudczer and Philip W. Lucas and James Hough},
  journal={Nature Astronomy},
  year={2017},
  volume={1},
  pages={690-696}
}
Polarization in stars was first predicted by Chandrasekhar1, who calculated a substantial linear polarization at the stellar limb for a pure electron-scattering atmosphere. This polarization will average to zero when integrated over a spherical star but could be detected if the symmetry was broken, for example, by the eclipse of a binary companion. Nearly 50 years ago, Harrington and Collins2 modelled another way of breaking the symmetry and producing net polarization—the distortion of a… 

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References

SHOWING 1-10 OF 78 REFERENCES

Polarization of Radiation from Distant Stars by the Interstellar Medium

Observational observations for the detection of partially polarized radiation from eclipsing binary stars at Yerkes Observatory establish observationally the effect pointed out by Chandrasekhar that the continuous radiation of early-type stars should be polarized.

The linear polarization of nearby bright stars measured at the parts per million level

We report observations of the linear polarization of a sample of 49 nearby bright stars measured to sensitivities of between �1 and �4 ×10 6 . The majority of stars in the sample show measurable

The linear polarisation of southern bright stars measured at the parts-per-million level

We report observations of the linear polarisation of a sample of 50 nearby southern bright stars measured to a median sensitivity of ∼4.4 ×10−6. We find larger polarisations and more highly polarised

Gravity darkening in rotating stars

Context. Interpretation of interferometric observations of rapidly rotating stars requires a good model of their surface effective temperature. Until now, laws of the form Teff ∝ g βff have been

PlanetPol: A Very High Sensitivity Polarimeter

We have built and used on several occasions an optical broadband stellar polarimeter, PlanetPol, which employs photoelastic modulators and avalanche photodiodes and achieves a photon‐noise–limited

COLDER AND HOTTER: INTERFEROMETRIC IMAGING OF β CASSIOPEIAE AND α LEONIS

Near-infrared interferometers have recently imaged a number of rapidly rotating A-type stars, finding levels of gravity darkening inconsistent with theoretical expectations. Here, we present new

Polarized Continuum Radiation from Stellar Atmospheres

Abstract Continuum scattering by free electrons can be significant in early type stars, while in late type stars Rayleigh scattering by hydrogen atoms or molecules may be important. Computer programs

POLARIZATION MEASUREMENTS OF HOT DUST STARS AND THE LOCAL INTERSTELLAR MEDIUM

Debris discs are typically revealed through the presence of excess emission at infrared wavelengths. Most discs exhibit excess at mid- and far-infrared wavelengths, analogous to the solar system’s

Rotational mixing in early-type main-sequence stars

We present quantitative observational investigations into the importance of rotationally induced mixing in late-O stars. First, we conduct non-LTE, hydrostatic, plane-parallel H/He model-atmosphere

ULTRAVIOLET INTERSTELLAR LINEAR POLARIZATION. V. ANALYSIS OF THE FINAL DATA SET

Using recent measurements of ultraviolet interstellar polarization, we have examined its relationship to ultraviolet extinction and to polarization and extinction measurements in the visible and
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