Publications (39)
Dynamical masses of Cepheids from the GAIA parallaxes
A. Gallenne, P. Kervella, A. Merand +2
The mass of a Cepheid is a fundamental parameter for studying the pulsation and evolution of intermediate-mass stars. But determining this variable has been a long-standing problem…
The nearby eclipsing stellar system delta Velorum. II. First reliable orbit for the eclipsing pair
T. Pribulla, A. Merand, P. Kervella +8
Context. The nearby multiple system delta Velorum contains a widely detached eclipsing binary and a third component. Aims. We take advantage of this system offering the opportunity…
The radius and effective temperature of the binary Ap star beta CrB from CHARA/FLUOR and VLT/NACO observations
H. Bruntt, P. Kervella, A. Merand +14
The prospects for using asteroseismology of rapidly oscillating Ap (roAp) stars are hampered by the large uncertainty in fundamental stellar parameters. Results in the literature f…
The non-thermal radio emitter HD 93250 resolved by long baseline interferometry
H. Sana, J. -B. Le Bouquin, M. De Becker +3
As the brightest O-type X-ray source in the Carina nebula, HD 93250 (O4 III(fc)) is X-ray overluminous for its spectral type and has an unusually hard X-ray spectrum. Two different…
Toward Direct Detection of Hot Jupiters with Precision Closure Phase: Calibration Studies and First Results from the CHARA Array
M. Zhao, J. D. Monnier, X. Che +12
Direct detection of thermal emission from nearby hot Jupiters has greatly advanced our knowledge of extrasolar planets in recent years. Since hot Jupiter systems can be regarded as…
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…
CRIRES high-resolution infrared spectroscopy of the long-period Cepheid l Car
N. Nardetto, E. Poretti, A. Gallenne +17
The dynamical structure of the atmosphere of Cepheids has been well studied in the optical. Several authors have found very interesting spectral features in the J band, but little…
An overview of the mid-infrared spectro-interferometer MATISSE: science, concept, and current status
A. Matter, B. Lopez, P. Antonelli +104
MATISSE is the second-generation mid-infrared spectrograph and imager for the Very Large Telescope Interferometer (VLTI) at Paranal. This new interferometric instrument will allow…
Colder and Hotter: Interferometric imaging of β Cassiopeiae and α Leonis
X. Che, J. D. Monnier, M. Zhao +9
Near-infrared interferometers have recently imaged a number of rapidly rotating A-type stars, finding levels of gravity darkening inconsistent with theoretical expectations. Here,…
First Results from the CHARA Array VII: Long-Baseline Interferometric Measurements of Vega Consistent with a Pole-On, Rapidly Rotating Star
J. P. Aufdenberg, A. Merand, V. Coude du Foresto +10
We have obtained high-precision interferometric measurements of Vega with the CHARA Array and FLUOR beam combiner in the K' band at projected baselines between 103m and 273m. The m…
A near-infrared interferometric survey of debris disc stars. II. CHARA/FLUOR observations of six early-type dwarfs
O. Absil, E. Di Folco, A. Merand +15
High-precision interferometric observations of six early-type main sequence stars known to harbour cold debris discs have been obtained in the near-infrared K band with the FLUOR i…
Transition disc nature of post-AGB binary systems confirmed by mid-infrared interferometry
A. Corporaal, J. Kluska, H. Van Winckel +4
Many properties of circumbinary discs around evolved post-asymptotic giant branch (post-AGB) binary systems are similar to those of protoplanetary discs around young stars. The def…
The nearby eclipsing stellar system delta Velorum III. Self-consistent fundamental parameters and distance
A. Merand, P. Kervella, T. Pribulla +6
The triple stellar system delta Vel (composed of two A-type and one F-type main sequence stars) is particularly interesting as it contains one of the nearest and brightest eclipsin…
Strong near-infrared emission in the sub-AU disk of the Herbig Ae star HD163296: evidence for refractory dust?
M. Benisty, A. Natta, A. Isella +12
We present new long-baseline spectro-interferometric observations of the HerbigAe star HD163296 obtained in the H and K bands with the AMBER instrument at VLTI. The observations co…
High resolution spectroscopy for Cepheids distance determination. I. Line asymmetry
N. Nardetto, D. Mourard, P. Kervella +3
The ratio of pulsation to radial velocity (the projection factor) is currently limiting the accuracy of the interferometric Baade-Wesselink method. This work aims at establishing a…
Fringe tracking performance monitoring: FINITO at VLTI
A. Merand, F. Patru, J. -P. Berger +2
Since April 2011, realtime fringe tracking data are recorded simultaneously with data from the VLTI/AMBER interferometric beam combiner. Not only this offers possibilities to post-…
First Resolved Images of the Eclipsing and Interacting Binary Beta Lyrae
M. Zhao, D. Gies, J. D. Monnier +12
We present the first resolved images of the eclipsing binary Beta Lyrae, obtained with the CHARA Array interferometer and the MIRC combiner in the H band. The images clearly show t…
Imaging and Modeling Rapidly Rotating Stars: Alpha Cephei and Alpha Ophiuchi
M. Zhao, J. D. Monnier, E. Pedretti +10
We present sub-milliarcseond resolution imaging and modeling of two nearby rapid rotators Alpha Cephei and Alpha Ophiuchi, obtained with the CHARA array - the largest optical/IR in…
CHARA Array K'-band Measurements of the Angular Dimensions of Be Star Disks
D. R. Gies, W. G. Bagnuolo, E. K. Baines +22
We present the first K'-band, long-baseline interferometric observations of the northern Be stars gamma Cas, phi Per, zeta Tau, and kappa Dra. The measurements were made with multi…
The ESPRI project: astrometric exoplanet search with PRIMA I. Instrument description and performance of first light observations
J. Sahlmann, T. Henning, D. Queloz +42
The ESPRI project relies on the astrometric capabilities offered by the PRIMA facility of the Very Large Telescope Interferometer for the discovery and study of planetary systems.…
A catalog of bright calibrator stars for 200-meter baseline near-infrared stellar interferometry
A. Merand, P. Borde, V. Coude du Foresto
We present in this paper a catalog of reference stars suitable for calibrating infrared interferometric observations. In the K band, visibilities can be calibrated with a precision…
Extended envelopes around Galactic Cepheids IV. T Monocerotis and X Sagittarii from mid-infrared interferometry with VLTI/MIDI
A. Gallenne, A. Merand, P. Kervella +3
Aims. We study the close environment of nearby Cepheids using high spatial resolution observations in the mid-infrared with the VLTI/MIDI instrument, a two-beam interferometric rec…
Discovery of a star sensitive to the spin of Sgr A*
K. Abd El Dayem, R. Abuter, N. Aimar +85
The paper reports the discovery of a faint main‑sequence star (S301) on an 8.7‑year, highly eccentric orbit around the Milky Way’s central black hole, whose high velocity makes its…
HARPS-N high spectral resolution observations of Cepheids II. The impact of the surface-brightness color relation on the Baade-Wesselink projection factor of eta Aql
N. Nardetto, W. Gieren, J. Storm +16
The Baade-Wesselink (BW) method of distance determination of Cepheids is used to calibrate the distance scale. Various versions of this method are mainly based on interferometry an…
A geometrical 1% distance to the short-period binary Cepheid V1334 Cygni
A. Gallenne, P. Kervella, N. R. Evans +18
Cepheid stars play a considerable role as extragalactic distances indicators, thanks to the simple empirical relation between their pulsation period and their luminosity. They over…
Four years' interferometric observations of Galactic binary Cepheids
A. Gallenne, A. Merand, P. Kervella +4
We give an update on our long-term program of Galactic Cepheids started in 2012, whose goal is to measure the visual orbits of Cepheid companions. Using the VLTI/PIONIER and CHARA/…
First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars
D. H. Berger, D. R. Gies, H. A. McAlister +8
We have measured the angular diameters of six M dwarfs with the CHARA Array, a long-baseline optical interferometer located at Mount Wilson Observatory. Spectral types range from M…
Observations of Microlensed Images with Dual-field Interferometry: On-sky Demonstration and Prospects
P. Mroz, S. Dong, A. Merand +57
Interferometric observations of gravitational microlensing events offer an opportunity for precise, efficient, and direct mass and distance measurements of lensing objects, especia…
Gaia22dkvLb: A Microlensing Planet Potentially Accessible to Radial-Velocity Characterization
Zexuan Wu, Subo Dong, Tuan Yi +50
We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensin…
HD 181068: A Red Giant in a Triply-Eclipsing Compact Hierarchical Triple System
A. Derekas, L. L. Kiss, T. Borkovits +41
Hierarchical triple systems comprise a close binary and a more distant component. They are important for testing theories of star formation and of stellar evolution in the presence…
Circumstellar material in the Vega inner system revealed by CHARA/FLUOR
O. Absil, E. di Folco, A. Merand +11
Only a handful of debris disks have been imaged up to now. Due to the need for high dynamic range and high angular resolution, very little is known about the inner planetary region…
Asteroseismology and interferometry of the red giant star epsilon Oph
A. Mazumdar, A. Merand, P. Demarque +16
The GIII red giant star epsilon Oph has been found to exhibit several modes of oscillation by the MOST mission. We interpret the observed frequencies of oscillation in terms of the…
Dust in the inner regions of debris disks around A stars
R. L. Akeson, D. R. Ciardi, R. Millan-Gabet +11
We present infrared interferometric observations of the inner regions of two A-star debris disks, beta Leo and zeta Lep, using the FLUOR instrument at the CHARA interferometer on b…
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…
The close environment of high-mass X-ray binaries at high angular resolution I. VLTI/AMBER and VLTI/PIONIER near-infrared interferometric observations of Vela X-1
E. Choquet, P. Kervella, J. -B. Le Bouquin +7
Recent improvements on the sensitivity and spectral resolution of X-ray observations have led to a better understanding of the properties of matter in the vicinity of High Mass X-r…
The orbital parameters of the del Cep inner binary system determined using 2019 HARPS-N spectroscopic data
N. Nardetto, V. Hocdé, P. Kervella +11
An inner companion has recently been discovered orbiting the prototype of classical Cepheids, delta Cep, whose orbital parameters are still not fully constrained. We collected new…
HR 6819 is a binary system with no black hole -- revisiting the source with infrared interferometry and optical integral field spectroscopy
A. J. Frost, J. Bodensteiner, Th. Rivinius +16
Two scenarios have been proposed to match the existing observational constraints of the object HR 6819. The system could consist of a close inner B-type giant plus a black hole (BH…
A new calibration of Galactic Cepheid Period-Luminosity relations from B to K bands, and a comparison to LMC PL relations
P. Fouque, P. Arriagada, J. Storm +8
The universality of the Cepheid Period-Luminosity relations has been under discussion since metallicity effects have been assumed to play a role in the value of the intercept and,…
Multiplicity of Galactic Cepheids from long-baseline interferometry~III. Sub-percent limits on the relative brightness of a close companion of ~Cephei
A. Gallenne, A. Merand, P. Kervella +11
We report new CHARA/MIRC interferometric observations of the Cepheid archetype Cep, which aimed at detecting the newly discovered spectroscopic companion. We reached a maximum…