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M. Shaw, Y.-H. Chu (UIUC)
B[e] supergiants are believed to have circumstellar disks and strong stellar winds. It has been suggested that the stellar wind consists of two components: a hot, fast polar wind and a cool, slow disk wind (Zickgraf et al. 1985, A&A 143, 421). For B[e] supergiants viewed edge-on along the disk, the fast polar wind is not observable.
In a recently obtained HST WFPC2 H\alpha image of the superbubble DEM 106 in the Large Magellenic Cloud, we observed two small HII regions with B dwarf central stars near the B[e] supergiant Hen S22. Hen S22 is known to be viewed along the disk and has a disk wind terminal velocity of 60 to 80 km/s. The HII regions have bright cores surrounded by bow-shock-like structures, suggesting an interaction between the B[e] supergiant wind and the HII regions. The high-dispersion eschelle spectra of the HII regions detect high velocity gas with a full width at zero intensity of ~1000 km/s. This further suggests that the HII regions are interacting with the hot, fast polar wind of Hen S22.
We have analyzed the WFPC2 image to derive the rms densities of the HII regions and their surrounding structures. We have used the echelle spectra to study the dynamics of the wind-HII region interaction and the expansion of the superbubble DEM 106. The results are presented in this poster.
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