S 111 and the polarization of the B[e] supergiants in the Magellanic Clouds

Citation
R. Melgarejo et al., S 111 and the polarization of the B[e] supergiants in the Magellanic Clouds, ASTRON ASTR, 377(2), 2001, pp. 581-588
Citations number
33
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY & ASTROPHYSICS
ISSN journal
14320746 → ACNP
Volume
377
Issue
2
Year of publication
2001
Pages
581 - 588
Database
ISI
SICI code
1432-0746(200110)377:2<581:S1ATPO>2.0.ZU;2-4
Abstract
We have obtained linear polarization measurements of the Large Magellanic C loud B[e] supergiant S 111 using optical imaging polarimetry. The intrinsic polarization found is consistent with the presence of an axisymmetric circ umstellar envelope. We have additionally estimated the electron density for S 111 using data from the literature and revisited the correlation between polarization and envelope parameters of the B[e] supergiant stars using mo re recent IR calibration color data. The data suggest that the polarization can be indeed explained by electron scattering. We have used Monte Carlo c odes to model the continuum polarization of the Magellanic B[e] supergiants . The results indicate that the electron density distribution in their enve lopes is closer to a homogeneous distribution rather than an r(-2) dependen ce. At the same time, the data are best fitted by a spherical distribution with density contrast than a cylindrical distribution. The data and the mod el results support the idea of the presence of an equatorial disk and of th e two-component wind model for the envelopes of the B[e] supergiants. Spect ropolarimetry would help further our knowledge of these envelopes.