AMBER/VLTI and MIDI/VLTI spectro-interferometric observations of the B[e] supergiant CPD-57° 2874. Size and geometry of the circumstellar envelope in the near- and mid-IR

A. Domiciano De Souza, T. Driebe, O. Chesneau, K. H. Hofmann, S. Kraus, A. S. Miroshnichenko, K. Ohnaka, R. G. Petrov, T. Preisbisch, P. Stee, G. Weigelt, F. Lisi, F. Malbet, A. Richichi

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35 Citations (Scopus)

Abstract

We present the first high spatial and spectral resolution observations of the circumstellar envelope (CSE) of a B[e] supergiant (CPD-570 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 2.2μm, and ≃12 × 15 mas or ≃30 × 38 AU at 12μm. 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 (UBVR cIc) 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.

Original languageEnglish
Pages (from-to)81-86
Number of pages6
JournalAstronomy and Astrophysics
Volume464
Issue number1
DOIs
Publication statusPublished - Mar 2007
Externally publishedYes

Keywords

  • Infrared: stars
  • Stars: early-type
  • Stars: emission-line, Be
  • Stars: mass-loss
  • Techniques: high angular resolution
  • Techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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