Interferometric View of Massive Active Hot and Dusty Stars
We present in the following recent results from the VLTI MIDI and AMBER instruments operating respectively at 10 and 2 μm. Up to now most of the interferometric results were obtained using the modulus of the visibility in order to estimate the global size and geometry of the circumstellar environments. Thanks to the spectrally resolved […]
Be stars: one ring to rule them all?
Aims.We report the theoretical spectral energy distributions (SEDs), Brγ line profiles, and visibilities for two scenarios that can explain the disk dissipation of active hot stars and account for the transition from the Be to the B spectroscopic phase.<BR /> Methods: .We use the SIMECA code to investigate two scenarios, the first one where the […]
New results from the VLTI on massive hot stars: First direct detection of a Keplerian disk around α Arae
We use the VLTI/AMBER instrument operating in the K band which combine a high angular resolution with a medium spectral resolution to study the kinematics of the inner part of α Arae’s disk and try to infer its rotation law. We obtain for the first time the direct evidence that the disk is in keplerian […]
Recent results from the SIMECA code and VLTI observations
We present recent results on active hot stars using the first VLTI/MIDI and VLTI/AMBER observations, and the SIMECA code developed by Stee (1994). α Arae was the first classical Be star observed with MIDI (June 2003) and AMBER (February 2005). The size of its circumstellar envelope was measured and thanks to the spectrally-resolved interferometric AMBER […]
The Mid-IR interferometer VLTI/MIDI and the study of hot star disks
The Mid-IR interferometric instrument MIDI on the Very Large Telescope Interferometer (VLTI) in June 2003 allows interferometric observations over the 8 μm-13 μm wavelength range, with a spatial resolution ranging from 5 to 20 milliarcsec, a spectral resolution of 30 and 250, and a point source sensitivity better than N = 4 mag (1 Jy). […]
Interferometric Studies of Hot Star Disks
Interferometry in the visible and in the IR now provides milliarcsecond spatial resolution and thus can be used for studying the circumstellar environment of hot star disks. After a brief introduction on the interferometric technique we will illustrate how the modulus and the phase of the visibility can be used to constrain the physics of […]
First VLTI/MIDI observations of a Be star: Alpha Arae
We present the first VLTI/MIDI observations of the Be star alpha Ara (HD 158 427), showing a nearly unresolved circumstellar disk in the N band. The interferometric measurements made use of the UT1 and UT3 telescopes. The projected baselines were 102 and 74 meters with position angles of 7 ° and 55°, respectively. These measurements […]
Recent Astrophysical Results from the VLTI
We present a review of recent astrophysical results based on data obtained with the ESO Very Large Telescope Interferometer (VLTI). The very first VLTI results have already been reviewed by Richichi & Paresce (2003). Remarkably, the first scientific results from the mid-infrared instrument MIDI, which emerge from science demonstration and guaranteed time observations, already cover […]
MWC297: Disk and Wind Spatially Resolved with VLTI/AMBER
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