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The Wind of the B[e] Supergiant Hen S22 Viewed through a Reflection Nebula in DEM L 106

Y. -H. Chu·C. -H. R. Chen·C. Danforth·B. C. Dunne·R. A. Gruendl·Y. Naze·M. S. Oey·S. D. Points
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Abstract

Narrow-band HST WFPC2 images reveal a bow-shock-like halo around the HII region N30B toward the B[e] supergiant Hen S22 located within the larger DEM L 106 nebula in the Large Magellanic Cloud. High-dispersion spectra of N30B show a narrow H-alpha emission component from the ionized gas; the velocity variations indicate a gas flow of -5 to -10 km/s in the vicinity of the HII regions, which is resultant from interactions with Hen S22's stellar wind and responsible for the bow-shock morphology. Spectra of N30B's halo show broad H-alpha profiles extending over >1000 km/s, similar to that of Hen S22, indicating that the halo is a reflection nebula of Hen S22. Broad-band morphologies of N30B's halo are also consistent with the reflection nebula interpretation. We use dust-scattering properties and the observed brightnesses of the reflection nebula and Hen S22 to constrain the reflection geometry. The reflected stellar H-alpha emission and absorption vary across the reflection nebula as a result of viewing S22's anisotropic wind across varying angles. This reflection nebula, together with the edge-on orientation of Hen S22's disk, provides an invaluable opportunity to study the disk and polar winds of a B[e] supergiant.

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Y. -H. Chu, C. -H. R. Chen, C. Danforth, B. C. Dunne, R. A. Gruendl, Y. Naze, M. S. Oey, S. D. Points. 2002-12-19. The Wind of the B[e] Supergiant Hen S22 Viewed through a Reflection Nebula in DEM L 106. https://arxiv.org/abs/astro-ph/0212462

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