Volume 469, Number 2, July II 2007
|Page(s)||587 - 593|
|Section||Interstellar and circumstellar matter|
|Published online||24 April 2007|
Resolving the B[e] star Hen 3-1191 at 10 m with VLTI/MIDI*
Centro de Radioastronomía y Astrofísica UNAM, Apartado Postal 3-72 (Xangari), Morelia, CP 58089 Michoacán, Mexico e-mail: email@example.com
2 Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
Accepted: 28 March 2007
We report spatially resolved, spectrally dispersed N-band observations of the B[e] star Hen 3-1191 with the MIDI instrument of the Very Large Telescope Interferometer. The object is resolved with a 40 m baseline and has an equivalent uniform disc diameter ranging from 24 mas at 8 to 36 mas at 13 . The MIDI spectrum and visibilities show a curvature which can arise from a weak silicate feature in which the object appears ≈15% larger than in the continuum, but this could result from a change in the object's geometry within the band. We then model Hen's 3-1191 spectral energy distribution (.4-60 ) and N-band visibilities. Because of the unknown nature of the object, we use a wide variety of models for objects with IR excesses. We find the observations to be consistent with a disc featuring an unusually high mass accretion and a large central gap almost void of matter, an excretion disc, and a binary made of two IR sources. We are unable to find a circumstellar shell model consistent with the data. We review the different hypotheses concerning the physical nature of the star and conclude that it is neither a Be supergiant nor a symbiotic star. However, we could not discriminate between the scenario of a young stellar object featuring an unusually strong FU Orionis-like outburst of mass accretion () and that of a protoplanetary nebula with an equatorial mass excretion rate . In both cases, taking the additional presence of an envelope or wind into account would result in lower mass flows.
Key words: stars: emission-line, Be / stars: individual: Hen 3-1191 / planetary systems: protoplanetary disks / infrared: stars / accretion, accretion disks / technique: interferometric
© ESO, 2007
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