by Domiciano de Souza, A., Driebe, T., Chesneau, O., Hofmann, K-H., Kraus, S., Miroshniichenko, A.S., Ohnaka, K., Petrov, R.G., Preibisch, Th., Stee, Ph. Weigelt, G.
We have obtained the first high spatial and spectral resolution observations of the circumstellar envelope (CSE) of a B[e] supergiant (CPD −57? 2874), performed with the Very Large Telescope Interferometer (VLTI). Spectra, visibilities and closure phase were obtained using the beam-combiner instruments AMBER (near-IR interferometry with three 8.3 m Unit Telescopes or UTs) and MIDI (mid-IR interferometry with two UTs). The interferometric observations of the CSE are well fitted by an elliptical Gaussian model with FWHM diameters varying linearly with wavelength.
Typical diameters measured are ~ 1.8 × 3.4 mas or ~ 4.5 × 8.5 AU (adopting a distance of 2.5 kpc) at 2.2 μm, and ~12 × 15 mas or ~ 30 × 38 AU at 12 μm. The size of the region emitting the Brγ flux is ~2.8 × 5.2 mas or ~7.0 × 13.0 AU. The major-axis position angle of the elongated CSE in the mid-IR (~144? ) agrees well with previous polarimetric data, hinting that the hot-dust emission originates in a disk-like structure.
In addition to the interferometric observations we also present new optical (U BV Rc Ic ) and near-IR (JHKL) broadband photometric observations of CPD −57? 2874. Our spectro-interferometric VLTI observations and data analysis support the non-spherical CSE paradigm for B[e] supergiants. These results are described in A&A, 464, 81
The following image was done by my PhD student Anthony Meilland and can be found on the ESO press release HERE.
