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The wind of the B[e] supergiant Henize S22 viewed through a reflection nebula in DEM L106

Publication Date
  • Hii Regions
  • Ism : Individual (Dem L106)
  • Magellanic Clouds
  • Stars : Emission-Line
  • Be
  • Stars : Mass Loss
  • Physical
  • Chemical
  • Mathematical & Earth Sciences :: Earth Sciences & Physical Geography [G02]
  • Physique
  • Chimie
  • Mathématiques & Sciences De La Terre :: Sciences De La Terre & Géographie Physique [G02]
  • Mathematics


Narrowband HST WFPC2 images reveal a bow-shock-like halo around the H II region N30B toward the B[e] supergiant Hen S22 located within the larger DEM L106 nebula in the Large Magellanic Cloud. High-dispersion spectra of N30B show a narrow Halpha emission component from the ionized gas; the velocity variations indicate a gas flow of - 5 to - 10 km s(-1) in the vicinity of the H II 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 Halpha profiles extending over more than 1000 km s(-1), similar to that of Hen S22, indicating that the halo is a reflection nebula of Hen S22. Broadband 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 Halpha emission and absorption vary across the reflection nebula as a result of viewing S22's anisotropic wind from different 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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