The observations of linear polarization in deep minima of WW Vul.
Abstract
In the course of photometric and polarimetric observations of WW Vul a broad photometrical minimum was registered, the deepest part of which being composed of three consecutive weakenings of brightness. The increase of linear polarization up to 5 - 6% (in V) was observed in each of them. The main part of polarized light may occur due to scattering of star radiation by dust particles of the circumstellar envelope. The contribution of this polarized radiation increases when the occultation of the star by the opaque dust cloud weakens the direct (non-polarized) radiation of the star. Additional source of light polarization is the alignment of non-spherical particles in the dust cloud, which are responsible for occultation. The symmetry axis of the circumstellar disc-like envelope of WW Vul may be oriented parallel to the local interstellar magnetic field. The observations confirm the hypothesis that the source of blue emission, observed in deep minima of such type stars, is the scattered radiation of the circumstellar dust.
- Publication:
-
Pisma v Astronomicheskii Zhurnal
- Pub Date:
- June 1988
- Bibcode:
- 1988PAZh...14..514G
- Keywords:
-
- Cosmic Dust;
- Light Curve;
- Linear Polarization;
- Polarized Light;
- Stellar Envelopes;
- Stellar Radiation;
- Color-Magnitude Diagram;
- Stellar Magnetic Fields;
- Astrophysics