Proceedings of the International Astronomical Union

Contributed Papers

Resolving the dusty torus and the mystery surrounding LMC red supergiant WOH G64

Keiichi Ohnakaa1, Thomas Driebea1, Karl-Heinz Hofmanna1, Gerd Weigelta1 and Markus Wittkowskia2

a1 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany email: kohnaka@mpifr-bonn.mpg.de

a2 European Southern Observatory, Karl-Schwarzschild-Str. 2, 85748 Garching, Germany

Abstract

We present mid-IR long-baseline interferometric observations of the red supergiant WOH G64 in the Large Magellanic Cloud with MIDI at the ESO's Very Large Telescope Interferometer (VLTI). Our MIDI observations of WOH G64 are the first VLTI observations to spatially resolve an individual stellar source in an extragalactic system. Our 2-D radiative transfer modeling reveals the presence of a geometrically and optically thick torus seen nearly pole-on. This model brings WOH G64 in much better agreement with the current evolutionary tracks for a 25 Mxs2299 star — about a half of the previous estimate of 40 Mxs2299 — and solves the serious discrepancy between theory and observation which existed for this object.

Keywords

  • techniques: interferometric;
  • infrared: stars;
  • circumstellar matter;
  • stars: evolution;
  • stars: late-type;
  • stars: mass loss;
  • supergiants;
  • Magellanic Clouds