Integral field spectroscopy of the Homunculus nebula / Espectroscopia de campo integral do Homúnculo de eta Carinae
AUTOR(ES)
Mairan Macedo Teodoro
DATA DE PUBLICAÇÃO
2005
RESUMO
The Homunculus nebula was mapped using the integral field technique and the results are presented in this dissertation. The observations were obtained in the J band in the range from 10620 Å to 12960 Å using the CIRPASS s IFU, which contains 499 hexagonal lenses. The spatial sampling is 0,25"/lens and the spectral resolution, set to R=3200. The [Fe II] λ12567 line allowed the identification of two structures in the NW lobe that had not been reported yet. Doppler tomography of this structures revealed a low density region placed in the NW lobe that is not seen in the optical images. Besides, the Little Homunculus was also detected both in the mapping of components of the [Fe II] λ12567 and in its velocity maps. In the Homunculus nebula, the polar regions (where the shock between the stellar bipolar wind and the internal wall of the lobes is stronger) are more opaque than the lobe walls. This can be verified by the decrease in the intensity of the [Fe II] λ12567 in the SE lobe and the enhancement of this line emission in the NW lobe. Emissions due to the equatorial disc were detected both in the H series (Paβ and Paγ) and the He I λ10830 as an intrinsic component up to distances greater than the aparent dimensions of the disc seen in the images taken in the optical range. The [Fe II] λ12567 also presents the component due to the equatorial emission. Low density regions in the torus involving the central source allow a beam of radiation to escape to large radii and thereby excite the gas contained in the equatorial disc. The best example of this effect was detected in the Doppler tomography of the He I λ10830 line, that revealed an intrinsic emission component which reaches distances larger than the aparent boundary of the NW lobe and was firstly mapped in this dissertation.
ASSUNTO(S)
estrelas massivas cirpass ifu cirpass ifu lbv homúnculo lbv massive stars homunculus
