First AMBER/VLTI Observations of Hot Massive Stars
AMBER is the first near infrared focal instrument of the VLTI. It combines three telescopes and produces spectrally resolved interferometric measures. This paper discusses some preliminary results of the first scientific observations of AMBER with three Unit Telescopes at medium (1500) and high (12000) spectral resolution. We derive a first set of constraints on the […]
SIMECA: a Code Dedicated to Active Hot Stars
Active hot stars are hot stars (Teff ≥ 8000 K) exhibiting emission lines (namely hydrogen lines) and IR excess which both originate in a circumstellar environment. In this paper we present in details the SIMECA (SImulation pour Etoiles Chaudes Actives) code which is the only code freely available to model the gaseous environment of active […]
Disk and wind evolution of the fast rotator Achernar.
We use spectral energy distributions (SEDs), Hα line profiles, and visibilities available in the literature to study Achernar’s envelope geometry and to propose a possible scenario for its circumstellar disk formation and dissipation. We use the SIMECA code to investigate possible geometries by comparing our synthetic results with spectroscopic and high angular resolution data from […]
In the intimacy of stars with AMBER at the VLTI
The AMBER instrument installed at the Very Large Telescope (VLT) combines the beams from three telescopes to produce spectrally dispersed interference fringes with milli-arcsecond angular scales in the near infrared. Three years after installation, first scientific observations have been carried out mostly during the Science Demonstration Time and the Guaranteed Time. The first science has […]
SIMulation pour Etoiles Chaudes Actives (SIMECA)
This SIMECA code, based on a radiative wind model, computes hydrogen line profiles, Spectral Energy Distributions (SEDs) and intensity maps which can be directly compared to high angular resolution observations. This code is dedicated to the modeling of active hot stars, mainly Be, B[e], LBV, WR and HAe/Be stars. It is possible to study the […]
First AMBER/VLTI Science
Three years after the installation of AMBER, the first scientific observations have been carried out mostly during Science Demonstration Time and Guaranteed Time. The first science has mainly focused on the environment of various types of stars. Observations described are: the discs and wind in the young star MWC297; the rotating gas envelope around the […]
First Observations of the Be Star α Ara with the VLTI
We aim to study the geometry and kinematics of the disk around the Be star α Arae as a function of wavelength, especially across the Brγ emission line. We use both the VLTI/MIDI and VLTI/AMBER instruments operating respectively in the N and K bands. Moreover, we have combined the high angular resolution provided with the […]
An asymmetry detected in the disk of <ASTROBJ>κ Canis Majoris</ASTROBJ> with AMBER/VLTI
Aims:We study the geometry and kinematics of the circumstellar environment of the Be star κ CMa in the Brγ emission line and its nearby continuum. <BR />Methods: We use the AMBER/VLTI instrument operating in the K band, which provides a spatial resolution of about 6 mas with a spectral resolution of 1500, to study the […]
First direct detection of a Keplerian rotating disk around the Be star α Arae using AMBER/VLTI
Aims:We aim to study the geometry and kinematics of the disk around the Be star α Arae as a function of wavelength, especially across the Brγ emission line. The main purpose of this paper is to understand the nature of the disk rotation around Be stars. <BR />Methods: We use the AMBER/VLTI instrument operating in […]
Disk and wind interaction in the young stellar object <ASTROBJ>MWC 297</ASTROBJ> spatially resolved with AMBER/VLTI
The young stellar object <ASTROBJ>MWC 297</ASTROBJ> is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT interferometer equipped with the AMBER instrument during its first commissioning run. AMBER/VLTI is currently the only near infrared interferometer that can observe spectrally dispersed visibilities. […]