Publications (31)
The dusty circumstellar environment of Betelgeuse during the Great Dimming as seen by VLTI/MATISSE
E. Cannon, M. Montargès, A. de Koter +23
The 'Great Dimming' of the prototypical red supergiant Betelgeuse, which occurred between December 2019 and April 2020, gives us unprecedented insight into the processes occurring…
VLTI-MATISSE L- and N-band aperture-synthesis imaging of the unclassified B[e] star FS Canis Majoris
K. -H. Hofmann, A. Bensberg, D. Schertl +58
Context: FS Canis Majoris (FS CMa, HD 45677) is an unclassified B[e] star surrounded by an inclined dust disk. The evolutionary stage of FS CMa is still debated. Perpendicular to t…
Enhanced Halpha activity at periastron in the young and massive spectroscopic binary HD200775
M. Benisty, K. Perraut, D. Mourard +15
Young close binaries clear central cavities in their surrounding circumbinary disk from which the stars can still accrete material. This process takes place within the very first a…
Mid-infrared circumstellar emission of the long-period Cepheid l Carinae resolved with VLTI/MATISSE
V. Hocdé, N. Nardetto, A. Matter +149
The nature of circumstellar envelopes (CSE) around Cepheids is still a matter of debate. The physical origin of their infrared (IR) excess could be either a shell of ionized gas, o…
GI2T/REGAIN spectro-interferometry with a new infrared beam combiner
G. Weigelt, D. Mourard, L. Abe +10
We have built an infrared beam combiner for the GI2T/REGAIN interferometer of the Observatoire de la Cote d'Azur. The beam combiner allows us to record spectrally dispersed Michels…
Revealing the sub-AU asymmetries of the inner dust rim in the disk around the Herbig Ae star R CrA
S. Kraus, K. -H. Hofmann, F. Malbet +5
Models predict that in the innermost AU of the disk around Herbig Ae/Be star, the dust disk forms a "puffed-up" inner rim, which should result in a strongly asymmetric brightness d…
The origin of hydrogen line emission for five Herbig Ae/Be stars spatially resolved by VLTI/AMBER spectro-interferometry
S. Kraus, K. -H. Hofmann, M. Benisty +14
To trace the accretion and outflow processes around YSOs, diagnostic spectral lines such as the BrG 2.166 micron line are widely used, although due to a lack of spatial resolution,…
Disentangling the wind and the disk in the close surrounding of the young stellar object MWC297 with AMBER/VLTI
Fabien Malbet, M. Benisty, W. J. De Wit +13
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-…
Resolving the compact dusty discs around binary post-AGB stars using N-band interferometry
P. Deroo, H. Van Winckel, M. Min +8
We present the first mid-IR long baseline interferometric observations of the circumstellar matter around binary post-AGB stars. Two objects, SX Cen and HD 52961, were observed usi…
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…
An investigation of the close environment of beta Cep with the VEGA/CHARA interferometer
N. Nardetto, D. Mourard, I. Tallon-Bosc +22
High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star bet…
VEGA/CHARA interferometric observations of Cepheids. I. A resolved structure around the prototype classical Cepheid delta Cep in the visible spectral range
N. Nardetto, A. Mérand, D. Mourard +23
The B-W method is used to determine the distance of Cepheids and consists in combining the angular size variations of the star, as derived from infrared surface-brightness relation…
Progress of the CHARA/SPICA project
C. Pannetier, D. Mourard, P. Berio +22
CHARA/SPICA (Stellar Parameters and Images with a Cophased Array) is currently being developed at Observatoire de la Côte d'Azur. It will be installed at the visible focus of the…
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…
First VLTI/MIDI observations of a Be star: Alpha Ara
Olivier Chesneau, A. Meilland, T. Rivinius +12
We present the first VLTI/MIDI observations of the Be star Alpha Ara, showing a nearly unresolved circumstellar disk in the N band. The interferometric measurements made use of the…
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…
Resolving the asymmetric inner wind region of the yellow hypergiant IRC+10420 with VLTI/AMBER in low and high spectral resolution mode
T. Driebe, J. H. Groh, K. -H. Hofmann +15
We obtained near-infrared long-baseline interferometry of IRC+10420 with the AMBER instrument of ESO's Very Large Telescope Interferometer (VLTI) in low and high spectral resolutio…
Critical study of the distribution of rotational velocities of Be stars; II: Differential rotation and some hidden effects interfering with the interpretation of the Vsin i parameter
J. Zorec, Y. Frémat, A. Domiciano de Souza +9
We assume that stars may undergo surface differential rotation to study its impact on the interpretation of and on the observed distribution of ratios of true r…
Visible and near-infrared spectro-interferometric analysis of the edge-on Be star Aquarii
E. S. G. de Almeida, A. Meilland, A. Domiciano de Souza +11
We present a detailed visible and near-IR spectro-interferometric analysis of the Be-shell star Aquarii from quasi-contemporaneous CHARA/VEGA and VLTI/AMBER observations. We m…
The extended atmosphere and circumstellar environment of the cool evolved star VX Sagittarii as seen by MATISSE
A. Chiavassa, K. Kravchenko, M. Montargès +50
Context. VX Sgr is a cool, evolved, and luminous red star whose stellar parameters are difficult to determine, which affects its classification. Aims. We aim to spatially resolve t…
Spectral and spatial imaging of the Be+sdO binary phi Persei
D. Mourard, J. D. Monnier, A. Meilland +25
The rapidly rotating Be star phi Persei was spun up by mass and angular momentum transfer from a now stripped-down, hot subdwarf companion. Here we present the first high angular r…
Direct constraint on the distance of y2 Velorum from AMBER/VLTI observations
F. Millour, R. G. Petrov, O. Chesneau +95
In this work, we present the first AMBER observations, of the Wolf-Rayet and O (WR+O) star binary system y2 Velorum. The AMBER instrument was used with the telescopes UT2, UT3, and…
The Pictoris b Hill sphere transit campaign. Paper I: Photometric limits to dust and rings
M. A. Kenworthy, S. N. Mellon, J. I. Bailey +33
Photometric monitoring of Beta Pictoris in 1981 showed anomalous fluctuations of up to 4% over several days, consistent with foreground material transiting the stellar disk. The su…
The asymmetric inner disk of the Herbig Ae star HD 163296 in the eyes of VLTI/MATISSE: evidence for a vortex?
J. Varga, M. Hogerheijde, R. van Boekel +133
Context. The inner few au region of planet-forming disks is a complex environment. High angular resolution observations have a key role in understanding the disk structure and the…
A dusty veil shading Betelgeuse during its Great Dimming
M. Montargès, E. Cannon, E. Lagadec +24
Red supergiants are the most common final evolutionary stage of stars that have initial masses between 8 and 35 times that of the Sun. During this stage, which lasts roughly 100,00…
Differential rotation in rapidly rotating early-type stars. I. Motivations for combined spectroscopic and interferometric studies
J. Zorec, Y. Fremat, A. Domiciano de Souza +7
Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation.…
Spatially resolving the hot CO around the young Be star 51 Ophiuchi
E. Tatulli, F. Malbet, F. Menard +6
51 Oph is one of the few young Be stars displaying a strong CO overtone emission at 2.3 microns in addition to the near infrared excess commonly observed in this type of stars. In…
Chromosphere of K giant stars Geometrical extent and spatial structure detection
P. Berio, T. Merle, F. Thevenin +19
We aim to constrain the geometrical extent of the chromosphere of non-binary K giant stars and detect any spatial structures in the chromosphere. We performed observations with the…
Images of Betelgeuse with VLTI/MATISSE across the Great Dimming
J. Drevon, F. Millour, P. Cruzalèbes +31
From Nov. 2019 to May 2020, the red supergiant star Betelgeuse experienced an unprecedented drop of brightness in the visible domain called the great dimming event. Large atmospher…
Calibrating the surface brightness - color relation for late-type red giants stars in the visible domain using VEGA/CHARA interferometric observations
N. Nardetto, A. Salsi, D. Mourard +14
The surface brightness - color relationship (SBCR) is a poweful tool for determining the angular diameter of stars from photometry. It was for instance used to derive the distance…
The Expanding Fireball of Nova Delphini 2013
G. H. Schaefer, T. ten Brummelaar, D. R. Gies +34
A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ej…