Compact Dust Shells Around Massive Evolved Stars
Abstract
Long baseline interferometric measurements in the 8-13 micron band using VLTI-MIDI have resolved dust around the Wolf-Rayet stars WR 106 and WR 95, the enigmatic NaSt1 which is likely a post-Luminous Blue Variable (LBV), and the prototypical LBV, AG Car. The dust shells around the WR stars gave gaussian half-widths of ∼ 25 to 45 mas and radiative transfer modeling of these shells show the dust being very close (tens of AU) to the star, existing in hostile conditions. The dust around NaSt1 seems to be a compact source embedded in an extended structure indicating current or very recent dust formation. NaSt1 may be a nascent WR emerging from a recent LBV stage and dust formation at this juncture is intriguing and may be a vital clue for the eventual identification of the evolutionary stage of this object. In the case of AG Car as well we marginally resolve dust very close to the central star, distinct from the detached nebula. Here also current dust formation is indicated and may be associated with a previously noted equatorial disk of molecular gas.
- Publication:
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Revista Mexicana de Astronomia y Astrofisica Conference Series
- Pub Date:
- May 2009
- Bibcode:
- 2009RMxAC..35Q.304R