- 3D image of HD 62623
- This image was created from the first combined image and motion measurements from the AMBER instrument on the Very Large Telescope Interferometer (VLTI) at ESO’s Paranal Observatory in Chile. It shows the mysterious disc of material around the brilliant supergiant star HD 62623. The picture has been colour coded to show the velocities of the material in the disc : blue indicates that the material is coming towards us, and red that it is receding.
The paper entitled "Imaging the spinning gas and dust in the disc around the supergiant A[e] star HD 62623" published recently in A&A describes milli-arcsecond-scale spectrally resolved images of this hot supergiant star which hosts a gas and dust disk. The authors used a novel technique for optical long baseline interferometry to recover the image cube of this star (hence the "3D"), which is similar to radio-interferometry self-calibration. By adding the differential phases to an image recovery process, it was for the first time possible to reconstruct "integral field spectra" of the system. This described technique of image reconstruction, here with AMBER and differential phases, greatly increases image quality relative to "classical" closure-phase imaging, since, at some point in this algorithm, one gets closer to phase-referencing imaging.
The resulting images show a wealth of information on HD 62623 : the disk inner rim of dust-sublimation is clearly resolved, showing the typical "skewed ring" shape for a vertical of barely curved rim, while the smaller gas disk is also resolved by the interferometer. In the emission line, the gas rotation is evidenced, together with a "doughnut-like" shape, which is a clue of an inner "cavity" of the disk. Keplerian rotation in that disk is a favored hypothesis, though not certain. The authors conclude that the previously indirectly detected companion star should be present inside that cavity, and is a key to explaining the formation of such a stable disk around a hot supergiant star.
The article can be read [on the A&A web site>http://adsabs.harvard.edu/abs/2011A...]
The press releases can be browsed by following these links :
F. Millour, A. Meilland, and co-authors