The Messenger Astronomical Science

To be or not to be Asymmetric? VLTI/MIDI and the Mass-loss Geometry of AGB Stars

No. 168 (June 2017), 28–31

Authors
  • Paladini, Claudia [Institut d’Astronomie et d’Astrophysique, Université libre de Bruxelles, Belgium]
  • Klotz, Daniela [Department of Astrophysics, University of Vienna, Austria]
  • Sacuto, Stephane [Department of Astrophysics, University of Vienna, Austria; Department of Physics and Astronomy, Division of Astronomy and Space Physics, University of Uppsala, Sweden]
  • Lagadec, Eric [Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Nice, France]
  • Wittkowski, Markus [European Southern Observatory (ESO)]
  • Richichi, Andrea [National Astronomical Research Institute of Thailand, Chiang Mai, Thailand]
  • Hron, Josef [Department of Astrophysics, University of Vienna, Austria]
  • Jorissen, Alain [Institut d’Astronomie et d’Astrophysique, Université libre de Bruxelles, Belgium]
  • Groenewegen, Martin A. T. [Koninklijke Sterrenwacht van België, Brussel, Belgium]
  • Kerschbaum, Franz [Department of Astrophysics, University of Vienna, Austria]
  • Verhoelst, Tijl [Belgian Institute for Space Aeronomy, Brussels, Belgium]
  • Rau, Gioia [Department of Astrophysics, University of Vienna, Austria]
  • Olofsson, Hans [Department of Earth and Space Sciences, Onsala Space Observatory, Sweden]
  • Zhao-Geisler, Ronny [Department of Earth Sciences, National Taiwan Normal University, Taipei, Taiwan]
  • Matter, Alexis [Laboratoire Lagrange, Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Nice, France]
PDF download
Section
Astronomical Science
Abstract

The Mid-infrared Interferometric instrument (MIDI) at the Very Large Telescope Interferometer (VLTI) has been used to spatially resolve the dust-forming region of 14 asymptotic giant branch (AGB) stars with different chemistry (O-rich and C-rich) and variability types (Miras, semi-regular, and irregular variables). The main goal of the programme was to detect deviations from spherical symmetry in the dust-forming region of these stars. All the stars of the sample are well resolved with the VLTI, and five are asymmetric and O-rich. This finding contrasts with observations in the near-infrared, where the C-rich objects are found to be more asymmetric than the O-rich ones. The nature of the asymmetric structures so far detected (dusty discs versus blobs)remains uncertain and will require imaging on milli-arcsecond scales.

DOI
Bibcode
2017Msngr.168...28P
Dates
Created: 2017-06-01/2017-06-30
Length
4 pages
Rights
Copyright European Southern Observatory

Cite this article:

Paladini, C., Klotz, D., Sacuto, S., Lagadec, E., Wittkowski, M., Richichi, A., Hron, J., Jorissen, A., Groenewegen, M., Kerschbaum, F., Verhoelst, T., Rau, G., Olofsson, H., Zhao-Geisler, R., Matter, A.; To be or not to be Asymmetric? VLTI/MIDI and the Mass-loss Geometry of AGB Stars. The Messenger 168 (June 2017): 28–31. https://doi.org/10.18727/0722-6691/5022