| Autor: |
Jean-Louis Monin, Markus Schöller, Philippe Stee, F. Rantakyrö, Markus Wittkowski, Karl-Heinz Hofmann, Didier Fraix-Burnet, Leonardo Testi, Jose H. Groh, Renaud Foy, Andrea Richichi, Thomas Driebe, Philippe Mathias, Olivier Chesneau, Alessandro Marconi, Fabien Malbet, Dieter Schertl, Gerd Weigelt, Florentin Millour, Stefan Kraus, Romain Petrov |
| Rok vydání: |
2008 |
| Předmět: |
|
| Zdroj: |
SPIE Proceedings. |
| ISSN: |
0277-786X |
| Popis: |
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. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
