Bibcode
Pereyra, A.; de Araújo, F. X.; Magalhães, A. M.; Borges Fernandes, M.; Domiciano de Souza, A.
Bibliographical reference
Astronomy and Astrophysics, Volume 508, Issue 3, 2009, pp.1337-1341
Advertised on:
12
2009
Journal
Citations
16
Refereed citations
11
Description
Aims. We study the geometry of the circumstellar environment of the B[e]
supergiant star GG Car. Methods: We present observations acquired
using the IAGPOL imaging polarimeter in combination with the
Eucalyptus-IFU spectrograph to obtain spectropolarimetric measurements
of GG Car across Hα at two epochs. Polarization effects along the
emission line are analysed using the Q-U diagram. In particular, the
polarization position angle (PA) obtained using the line effect is able
to constrain the symmetry axis of the disk/envelope. Results: By
analysing the fluxes, GG Car shows an increase in its double-peaked
Hα line emission relative to the continuum within the interval of
our measurements (~43 days). The depolarization line effect around
Hα is evident in the Q-U diagram for both epochs, confirming that
light from the system is intrinsically polarized. A rotation of the PA
along Hα is also observed, indicating a counter-clockwise rotating
disk. The intrinsic PA calculated using the line effect (~85°) is
consistent between our two epochs, suggesting a clearly defined symmetry
axis of the disk.
Based on observations obtained at the Observatório do Pico dos
Dias, LNA/MCT, Itajubá, Brazil.