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Proceedings Paper

VLTI-AMBER observations of Eta Carinae with the FINITO fringe tracker and spectral resolution 12000
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Paper Abstract

We present interferometric near-infrared observations of the Luminous Blue Variable (LBV) η Car using the Very Large Telescope Interferometer (VLTI) and the AMBER instrument of the European Southern Observatory (ESO). A high spatial resolution of 5 mas (~11.5 AU) and a high spectral resolution R = λ/Δλ=1500 and 12000 were obtained. Some of the data was recorded using the fringe tracker FINITO. The observations were obtained in the wavelength range around both the He I 2.059 μm and the Brγ 2.166 μm emission lines. The AMBER interferograms allow the investigation of the wavelength dependence of η Car's visibility, wavelength-differential phase, and closure phase. If we fit Hillier et al. model visibilities to the observations, we obtain 50% encircled-energy diameters of 4.2, 6.5 and 9.6 mas in the 2.17 μm continuum, the He I, and the Brγ emission lines, respectively. In the continuum, an elongation along a position angle of 120° ± 15° was derived from the visibilities. The VLTI observations support theoretical models of anisotropic winds from fast-rotating, luminous hot stars with enhanced high-velocity mass loss near the pole.

Paper Details

Date Published: 28 July 2008
PDF: 11 pages
Proc. SPIE 7013, Optical and Infrared Interferometry, 701303 (28 July 2008); doi: 10.1117/12.796204
Show Author Affiliations
Gerd Weigelt, Max-Planck-Institut für Radioastronomie (Germany)
Olivier Chesneau, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur (France)
Thomas Driebe, Max-Planck-Institut für Radioastronomie (Germany)
Renaud Foy, Ctr. de Recherche Astronomique de Lyon, Univ. Claude Bernard, CNRS (France)
Didier Fraix-Burnet, Lab. d'Astrophysique de Grenoble, Univ. Joseph Fourier, CNRS (France)
Jose H. Groh, Max-Planck-Institut für Radioastronomie (Germany)
Karl-Heinz Hofmann, Max-Planck-Institut für Radioastronomie (Germany)
Stefan Kraus, Max-Planck-Institut für Radioastronomie (Germany)
Fabien Malbet, Lab. d'Astrophysique de Grenoble, Univ. Joseph Fourier, CNRS (France)
Alessandro Marconi, Univ. di Firenze (Italy)
Philippe Mathias, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur (France)
Florentin Millour, Max-Planck-Institut für Radioastronomie (Germany)
Jean-Louis Monin, Lab. d'Astrophysique de Grenoble, Univ. Joseph Fourier, CNRS (France)
Romain G. Petrov, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur (France)
Frederik Rantakyrö, European Southern Observatory (Chile)
Andrea Richichi, European Southern Observatory (Germany)
Dieter Schertl, Max-Planck-Institut für Radioastronomie (Germany)
Markus Schöller, European Southern Observatory (Germany)
Philippe Stee, Univ. Nice Sophia Antipolis, CNRS, Observatoire de la Côte d'Azur (France)
Leonardo Testi, European Southern Observatory (Germany)
Markus Wittkowski, European Southern Observatory (Germany)


Published in SPIE Proceedings Vol. 7013:
Optical and Infrared Interferometry
Markus Schöller; William C. Danchi; Françoise Delplancke, Editor(s)

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