The binary Be star δ Scorpii at high spectral and spatial resolution. II. The circumstellar disk evolution after the periastron
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared (IR) excess and emission lines. The influence of binarity on these phenomena remains controversial. <BR /> Aims: We followed the evolution of the environment surrounding the binary Be star δ Scorpii one year before […]
The relationship between γ Cassiopeiae’s X-ray emission and its circumstellar environment. II. Geometry and kinematics of the disk from MIRC and VEGA instruments on the CHARA Array
Context.γ Cas is thought to be the prototype of classical Be stars and is the most studied object among this group. However, as for all Be stars, the origin and the physics of its circumstellar disk responsible for the observed near IR-excess, emission lines, and peculiar X-ray emission is still being debated. <BR /> Aims: […]
First spectro-interferometric survey of Be stars. I. Observations and constraints on the disk geometry and kinematics
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed infrared-excess and emission lines. The phenomena involved in the disk formation still remain highly debated. <BR /> Aims: To progress in the understanding of the physical process or processes responsible for the mass ejections and […]
Spatially resolving the outer atmosphere of the M giant BK Virginis in the CO first overtone lines with VLTI/AMBER
Context. The mass-loss mechanism in normal K-M giant stars with small variability amplitudes is not yet understood, although the majority among red giant stars are precisely of this type. <BR /> Aims: We present high-spatial and high-spectral resolution observations of the M7 giant BK Vir with AMBER at the Very Large Telescope Interferometer (VLTI). Our […]
The 2011 outburst of the recurrent nova <ASTROBJ>T Pyxidis</ASTROBJ>. Evidence for a face-on bipolar ejection
<BR /> Aims: T Pyx is the first recurrent nova ever historically studied. It was seen in outburst six times between 1890 and 1966 and then not for 45 years. We report on near-IR interferometric observations of the recent outburst of 2011. <BR /> Methods: We obtained near-IR observations of <ASTROBJ>T Pyx</ASTROBJ> at dates ranging […]
The binary Be star δ Scorpii at high spectral and spatial resolution. I. Disk geometry and kinematics before the 2011 periastron
Context. Classical Be stars are hot non-supergiant stars surrounded by a gaseous circumstellar disk that is responsible for the observed IR-excess and emission lines. The influence of binarity on these phenomena remains controversial. Aims.δ Sco is a binary system whose primary suddenly began to exhibit the Be phenomenon at the last periastron in 2000. We […]
Kinematics and geometrical study of the Be stars 48 Persei and ψ Persei with the VEGA/CHARA interferometer
Context. Five different physical processes might be responsible for the formation of decretion disks around Be stars: fast rotation of the star, stellar pulsations, binarity, stellar winds, and magnetic fields. Our observations indicate that fast rotation seems to produce a disk in Keplerian rotation, at least in the specific case of the two stars observed. […]
The Galactic unclassified B[e] star HD 50138. II. Interferometric constraints on the close circumstellar environment
Context. HD 50138 is a southern star that presents the B[e] phenomenon, but its evolutionary stage is still not well known. This object presents spectral variability, which can be explained by outbursts or shell phases. Spectropolarimetric observations have shown the presence of a non-spherically symmetric circumstellar environment that is responsible for the B[e] phenomenon. However, […]
VLTI/AMBER spectro-interferometry of the Herbig Be star MWC 297 with spectral resolution 12 000
Context. Circumstellar disks and outflows play a fundamental role in star formation. Infrared spectro-interferometry allows the inner accretion-ejection region to be resolved. <BR /> Aims: We study the disk and Brγ-emitting region of <ASTROBJ>MWC 297</ASTROBJ> with high spatial and spectral resolution and compare our observations with disk-wind models. <BR /> Methods: We measured interferometric visibilities, […]
Imaging the spinning gas and dust in the disc around the supergiant A[e] star HD 62623
Context. To progress in the understanding of evolution of massive stars one needs to constrain the mass-loss and determine the phenomenon responsible for the ejection of matter an its reorganization in the circumstellar environment <BR /> Aims: In order to test various mass-ejection processes, we probed the geometry and kinematics of the dust and gas […]