Paper: astro-ph/0510736
Date: Wed, 26 Oct 2005 13:47:37 GMT (168kb)

Title: The vicinity of the galactic supergiant B[e] star CPD -57 2874 from
near- and mid-IR long baseline spectro-interferometry with the VLTI (AMBER
and MIDI)

Authors: A. Domiciano de Souza, T. Driebe, O. Chesneau, K.-H. Hofmann, S.
Kraus, A. S. Miroshnichenko, K. Ohnaka, R. G. Petrov, Th. Preibisch, P. Stee,
G. Weigelt

Comments: To appear in the ASP proceedings of the Workshop "Stars with the B[e]
Phenomenon"
\\
We present the first spectro-interferometric observations of the
circumstellar envelope (CSE) of a B[e] supergiant (CPD -57 2874), performed
with the Very Large Telescope Interferometer (VLTI) 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). Our observations of the CSE
are well fitted by an elliptical Gaussian model with FWHM diameters varying
linearly with wavelength. Typical diameters measured are $\simeq1.8\times3.4$
mas or $\simeq4.5\times8.5$ AU (adopting a distance of 2.5 kpc) at
$2.2\micron$, and $\simeq12\times15$ mas or $\simeq30\times38$ AU at
$12\micron$. We show that a spherical dust model reproduces the SED but it
underestimates the MIDI visibilities, suggesting that a dense equatorial disk
is required to account for the compact dust-emitting region observed. Moreover,
the derived major-axis position angle in the mid-IR ($\simeq144\degr$) agrees
well with previous polarimetric data, hinting that the hot-dust emission
originates in a disk-like structure. Our results support the non-spherical CSE
paradigm for B[e] supergiants.

\\ ( http://arXiv.org/abs/astro-ph/0510736 , 168kb)