A mid-infrared imaging survey of post-AGB stars

Eric Lagadec, Tijl Verhoelst, Djamel Mékarnia, Olga Suárez, Albert A. Zijlstra, Philippe Bendjoya, Ryszard Szczerba, Olivier Chesneau, Hans Van Winckel, Michael J. Barlow, Mikako Matsuura, Janet E. Bowey, Silvia Lorenz-Martins, Tim Gledhill

    Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

    Abstract

    Post-AGB stars are key objects for the study of the dramatic morphological changes of low- to intermediate-mass stars on their evolution from the Asymptotic Giant Branch (AGB) towards the planetary nebula stage. There is growing evidences that binary interaction processes may very well have a determining role in the shaping process of many objects, but so far direct evidence is still weak. We aim at a systematic study of the dust distribution around a large sample of post-AGB stars as a probe of the symmetry breaking in the nebulae around these systems. We used imaging in the mid-infrared to study the inner part of these evolved stars to probe direct emission from dusty structures in the core of post-AGB stars in order to better understand their shaping mechanisms. We imaged a sample of 93 evolved stars and nebulae in the mid-infrared using VISIR/VLT, T-Recs/Gemini South and Michelle/Gemini North. We found that all the the proto-planetary nebulae we resolved show a clear departure from spherical symmetry. 59 out of the 93 observed targets appear to be non resolved. The resolved targets can be divided in two categories. The nebulae with a dense central core, that are either bipolar and multipolar. The nebulae with no central core have an elliptical morphology. The dense central torus observed likely host binary systems which triggered fast outflows that shaped the nebulae. © 2012 International Astronomical Union.
    Original languageEnglish
    Title of host publicationProceedings of the International Astronomical Union|Proc. Int. Astron. Union
    Pages59-62
    Number of pages3
    Volume7
    DOIs
    Publication statusPublished - Jul 2011

    Publication series

    NameIAU Symposium

    Keywords

    • infrared: stars
    • Stars: AGB and post-AGB
    • surveys

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