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An Improved Model of SiO Maser Emission in Miras
M. D. Gray, M. Wittkowski, M. Scholz +3
We describe a combined dynamic atmosphere and maser propagation model of SiO maser emission in Mira variables. This model rectifies many of the defects of an earlier model of this…
Asymmetric silicate dust distribution toward the silicate carbon star BM Gem
Keiichi Ohnaka, Hideyuki Izumiura, Christoph Leinert +3
Silicate carbon stars show the 10 micron silicate emission, despite their carbon-rich photospheres. They are considered to have circumbinary or circum-companion disks, which serve…
Spatially resolved dusty torus toward the red supergiant WOH G64 in the Large Magellanic Cloud
Keiichi Ohnaka, Thomas Driebe, Karl-Heinz Hofmann +2
We present N-band spectro-interferometric observations of the red supergiant WOH G64 in the Large Magellanic Cloud (LMC) using MIDI at the Very Large Telescope Interferometer (VLTI…
The close circumstellar environment of the semi-regular S-type star Pi^1 Gruis
Stéphane Sacuto, Alain Jorissen, Pierre Cruzalèbes +4
We study the close circumstellar environment of the nearby S-type star Pi^1 Gruis using high spatial-resolution, mid-infrared observations from the ESO/VLTI. Spectra and visibiliti…
Resolving the inner active accretion disk around the Herbig Be star MWC 147 with VLTI/MIDI+AMBER spectro-interferometry
Stefan Kraus, Thomas Preibisch, Keiichi Ohnaka
We studied the geometry of the inner (AU-scale) circumstellar environment around the Herbig Be star MWC 147. Combining, for the first time, near- (NIR, K band) and mid-infrared (MI…
J, H, K spectro-interferometry of the Mira variable S Orionis
M. Wittkowski, D. A. Boboltz, T. Driebe +4
Aims: We present J, H, K interferometry with a spectral resolution of 35 for the Mira variable S Orionis. We aim at measuring the diameter variation as a function of wavelength tha…
Imaging the oxygen-rich disk toward the silicate carbon star EU And
Keiichi Ohnaka, David A. Boboltz
We present multi-epoch high-angular resolution observations of 22 GHz H2O masers toward the silicate carbon star EU And to probe the spatio-kinematic distribution of oxygen-rich ma…
Detection of an inner gaseous component in a Herbig Be star accretion disk: Near- and mid-infrared spectro-interferometry and radiative transfer modeling of MWC 147
Stefan Kraus, Thomas Preibisch, Keiichi Ohnaka
We study the geometry and the physical conditions in the inner (AU-scale) circumstellar region around the young Herbig Be star MWC 147 using long-baseline spectro-interferometry in…
The Mira variable S Ori: Relationships between the photosphere, molecular layer, dust shell, and SiO maser shell at 4 epochs
M. Wittkowski, D. A. Boboltz, K. Ohnaka +2
We present the first multi-epoch study that includes concurrent mid-infrared and radio interferometry of an oxygen-rich Mira star. We obtained mid-infrared interferometry of S Ori…
Near-infrared polarimetric study of the bipolar nebula IRAS 19312+1950
K. Murakawa, J. Nakashima, K. Ohnaka +1
We obtained H-band polarimetric data of IRAS 19312+1950 using the near-infrared camera (CIAO) on the 8 m Subaru telescope. In order to investigate the physical properties of the ce…
Visual/infrared interferometry of Orion Trapezium stars: Preliminary dynamical orbit and aperture synthesis imaging of the Theta 1 Orionis C system
S. Kraus, Y. Y. Balega, J. -P. Berger +10
Located in the Orion Trapezium cluster, Theta 1 Orionis C is one of the youngest and nearest high-mass stars (O5-O7) and also known to be a close binary system. Using new multi-epo…
Temporal variations of the outer atmosphere and the dust shell of the carbon-rich Mira variable V Oph probed with VLTI/MIDI
Keiichi Ohnaka, T. Driebe, G. Weigelt +1
We present the first multi-epoch N-band spectro-interferometric observations of the carbon-rich Mira variable V Oph using MIDI at the ESO's Very Large Telescope Interferometer. Our…
3D Radiative Transfer Modeling of Clumpy Dust Tori Around AGN
S. F. Hoenig, T. Beckert, K. Ohnaka +1
We present 3-dimensional radiative transfer models for clumpy dust tori around AGN. Our method combines Monte Carlo simulations of individual dust clouds with the actual 3-dimensio…
Radiative Transfer Modeling of Three-Dimensional Clumpy AGN Tori and its Application to NGC 1068
S. F. Hoenig, T. Beckert, K. Ohnaka +1
Recent observations of NGC 1068 and other AGN support the idea of a geometrically and optically thick dust torus surrounding the central supermassive black hole and accretion disk…
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)
A. Domiciano de Souza, T. Driebe, O. Chesneau +8
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 Interfero…
VLTI/AMBER and VLTI/MIDI spectro-interferometric observations of the B[e] supergiant CPD-57 2874
A. Domiciano de Souza, T. Driebe, O. Chesneau +11
We present the first high spatial and spectral observations of the circumstellar envelope (CSE) of a B[e] supergiant (CPD), performed with the Very Large Telescope Interf…
Disk and wind interaction in the young stellar object MWC 297 spatially resolved with VLTI/AMBER
F. Malbet, M. Benisty, W. J. De Wit +15
The young stellar object MWC 297 has been observed with the VLT interferometer equipped with the AMBER instrument. MWC 297 has been spatially resolved in the continuum with a visib…
Comparison of dynamical model atmospheres of Mira variables with mid-infrared interferometric and spectroscopic observations
K. Ohnaka, M. Scholz, P. R. Wood
We present a comparison of dynamical model atmospheres with mid-infrared (~11 micron) interferometric and spectroscopic observations of the Mira variable o Cet. The dynamical model…
High angular resolution N-band observation of the silicate carbon star IRAS08002-3803 with the VLTI/MIDI instrument
Keiichi Ohnaka, T. Driebe, K. -H. Hofmann +10
We present the results of N-band spectro-interferometric observations of the silicate carbon star IRAS08002-3803 with the MID-infrared Interferometric instrument (MIDI) at the Very…
VLTI observations of AGB stars
M. Wittkowski, D. A. Boboltz, T. Driebe +1
We report on recent observations of AGB stars obtained with the VLT Interferometer (VLTI). We illustrate in general the potential of interferometric measurements to study stellar a…
Multi-wavelength interferometry of evolved stars using VLTI and VLBA
M. Wittkowski, D. A. Boboltz, T. Driebe +1
We report on our project of coordinated VLTI/VLBA observations of the atmospheres and circumstellar environments of evolved stars. We illustrate in general the potential of interfe…
Warm water vapor envelope in Mira variables and its effects on the apparent size from the near-infrared to the mid-infrared
Keiichi Ohnaka
We present a possible interpretation for the increase of the angular diameter of the Mira variables o Cet, R Leo, and chi Cyg from the K band to the 11 micron region revealed by th…
Warm water vapor envelope in the supergiants alf Ori and alf Her and its effects on the apparent size from the near-infrared to the mid-infrared
Keiichi Ohnaka
We present a possible interpretation for the increase of the angular diameter of the supergiants alf Ori (M1-2 Ia-Ibe) and alf Her (M5 Ib-II) from the K band to the 11 micron regio…
Interferometric observations of the Mira star o Ceti with the VLTI/VINCI instrument in the near-infrared
H. C. Woodruff, M. Eberhardt, T. Driebe +9
We present K-band commissioning observations of the Mira star prototype o Cet obtained at the ESO Very Large Telescope Interferometer (VLTI) with the VINCI instrument and two sider…