423 citations · 1.7k across the 35 of their papers we have counts for
21 papers · 1 filter
Gaia DR3 high radial velocity stars: Genuine fast-moving objects or outliers?
D. Katz, A. Gómez, E. Caffau +39
The third Gaia data release includes 33.8 million radial velocity measurements, extending to a magnitude of G_RVS = 14. To reach this magnitude limit, spectra were processed down t…
The impact of stellar rotations and binaries on the shape of upper main sequence near turn off in open cluster NGC\,6067
Jayanand Maurya, Yu Zhang, Sebastian Kamann +7
We present the analysis of the extended Main Sequence Turn-Off (eMSTO) in the open cluster NGC\,6067. We derive the projected rotational velocity, \textit{v}sin\textit{i}, of the s…
Be and Bn stars: Balmer discontinuity and stellar-class relationship
Y. R. Cochetti, J. Zorec, L. S. Cidale +5
A significant number of Be stars show a second Balmer discontinuity (sBD) attributed to an extended circumstellar envelope (CE). The fast rotational velocity of Be stars undoubtedl…
HR 8844: a new transition object between the Am stars and the HgMn stars ?
R. Monier, M. Gebran, F. Royer +2
While monitoring a sample of apparently slowly rotating superficially normal early A stars, we have discovered that HR 8844 (A0 V), is actually a new Chemically Peculiar star. We h…
Photometric and spectroscopic variability of the B5IIIe star HD 171219
L. Andrade, E. Janot-Pacheco, M. Emilio +11
We analyzed the star HD 171219, one of the relatively bright Be stars observed in the seismo field of the CoRoT satellite, in order to determine its physical and pulsation characte…
Gravity darkening in stars with surface differential rotation
J. Zorec, M. Rieutord, F. Espinosa Lara +3
The interpretation of stellar apparent fundamental parameters must be treated consistently with the characteristics of their surface rotation law. We develop a model to determine t…
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 ro…
A test field for Gaia. Radial velocity catalogue of stars in the South Ecliptic Pole
Y. Frémat, M. Altmann, E. Pancino +25
Gaia is a space mission currently measuring the five astrometric parameters as well as spectrophotometry of at least 1 billion stars to G = 20.7 mag with unprecedented precision. T…
KIC 9533489: a genuine gamma Doradus-delta Scuti Kepler hybrid pulsator with transit events
Zs. Bognár, P. Lampens, Y. Frémat +8
Context: Several hundred candidate hybrid pulsators of type A-F have been identified from space-based observations. Their large number allows both statistical analyses and detailed…
Discrete absorption components in the massive LBV Binary MWC 314
A. Lobel, C. Martayan, M. Corcoran +2
We investigate the physical properties of large-scale wind structures around massive hot stars with radiatively-driven winds. We observe Discrete Absorption Components (DACs) in op…
A search for pulsations in the HgMn star HD 45975 with CoRoT photometry and ground-based spectroscopy
T. Morel, M. Briquet, M. Auvergne +28
The existence of pulsations in HgMn stars is still being debated. To provide the first unambiguous observational detection of pulsations in this class of chemically peculiar object…
Multisite spectroscopic seismic study of the beta Cep star V2052 Oph: inhibition of mixing by its magnetic field
M. Briquet, C. Neiner, C. Aerts +29
We used extensive ground-based multisite and archival spectroscopy to derive observational constraints for a seismic modelling of the magnetic beta Cep star V2052 Ophiuchi. The lin…
Time resolved spectroscopy of BD+46 442: gas streams and jet creation in a newly discovered evolved binary with a disk
N. Gorlova, H. Van Winckel, C. Gielen +9
Previous studies have shown that many post-AGB stars with dusty disks are associated with single-lined binary stars. To verify the binarity hypothesis on a larger sample, we starte…
Mass ratio from Doppler beaming and Rømer delay versus ellipsoidal modulation in the Kepler data of KOI-74
S. Bloemen, T. R. Marsh, P. Degroote +18
We present a light curve analysis and radial velocity study of KOI-74, an eclipsing A star + white dwarf binary with a 5.2 day orbit. Aside from new spectroscopy covering the orbit…
Modeling the Asymmetric Wind of Massive LBV Binary MWC 314
A. Lobel, J. Groh, K. Torres Dozinel +13
Spectroscopic monitoring with Mercator-HERMES over the past two years reveals that MWC 314 is a massive binary system composed of an early B-type primary LBV star and a less-lumino…
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.…
Photometric variability of the Be star CoRoT-ID 102761769
M. Emilio, L. Andrade, E. Janot-Pacheco +16
Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, wich exhibit Balmer emission lines and often a near infrared excess originating…
X-shooter, NACO, and AMBER observations of the LBV Pistol Star \footnote{Based on ESO runs 85.D-0182A, 085.D-0625AC}
Christophe Martayan, Ronny Blomme, Jean-Baptiste Le Bouquin +15
We present multi-instruments and multi-wavelengths observations of the famous LBV star Pistol Star. These observations are part of a larger program about early O stars at different…
CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Mon
M. Desmet, Y. Fr'emat, F. Baudin +15
Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution échelle spectra led to the determination of improved and consistent fu…
A semi-automatic procedure for abundance determination of A- and F-type stars
S. Hekker, Y. Fremat, P. Lampens +4
A variety of physical processes leading to different types of pulsations and chemical compositions is observed among A- and F-type stars. To investigate the underlying mechanisms r…
Pulsations, chemical composition and multiplicity in main-sequence A- and F-type stars
S. Hekker, Y. Frémat, P. Lampens +1
The region in the HR-diagram where the main sequence intersects the classical instability strip hosts A- and F-type stars exhibiting a rich variety of physical phenomena, such as p…