A5038678435- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysical Phenomena and Observations
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Scientific Research and Discoveries
- Spacecraft and Cryogenic Technologies
- Geophysics and Gravity Measurements
- Colorectal Cancer Screening and Detection
- ZnO doping and properties
- Quantum Dots Synthesis And Properties
- COVID-19 and healthcare impacts
- Pulsars and Gravitational Waves Research
- Superconducting Materials and Applications
- Adaptive optics and wavefront sensing
- Chalcogenide Semiconductor Thin Films
- Global Cancer Incidence and Screening
- High-pressure geophysics and materials
- GNSS positioning and interference
- Ionosphere and magnetosphere dynamics
University of Valparaíso
2010-2019
Atomic Energy Commission of Syria
2016
Observatoire de la Côte d’Azur
2008-2010
Centre National de la Recherche Scientifique
2006-2010
Institut de Biologie Valrose
2010
Context. To progress in the understanding of evolution massive stars one needs to constrain mass-loss and determine phenomenon responsible for ejection matter an its reorganization circumstellar environment Aims. In order test various mass-ejection processes, we probed geometry kinematics dust gas surrounding A[e] supergiant HD 62623. Methods. We used combined high spectral spatial resolution covered by VLTI/AMBER instrument. Thanks a new multiwavelength optical/IR interferometry imaging...
Context. Classical Be stars are hot non-supergiant surrounded by a gaseous circumstellar disk that is responsible for the observed infrared-excess and emission lines. The phenomena involved in formation still remain highly debated.
Zinc sulfide (ZnS) thin films have been deposited on Si (1 0 0) substrate using ultrasonic spray pyrolysis. X-ray diffraction (XRD) analysis revealed that the are (0 2) preferentially oriented with c-axis-oriented wurtzite structure. The crystallinity has found to improve film thickness in 180–6000 nm range. Film structure analyzed by XRD, scanning electron microscope, FTIR, and Raman spectroscopies, while stoichiometry verified energy-dispersive spectroscopy particle-induced emission...
Aims. We use spectral energy distributions (SEDs), Hα line profiles, and visibilities available in the literature to study Achernar's envelope geometry propose a possible scenario for its circumstellar disk formation dissipation.
Classical Be stars are hot non-supergiant 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. delta Sco binary system whose primary suddently began to exhibit phenomenon at last periastron in 2000. We want constrain geometry kinematics its environment. star between 2007 2010 using spectrally-resolved interferometry with VLTI/AMBER CHARA/VEGA instruments. found orbital...
Context. Variable B supergiants (BSGs) constitute a heterogeneous group of stars with complex photometric and spectroscopic behaviours. They exhibit mass-loss variations experience different types oscillation modes, there is growing evidence that variable stellar winds photospheric pulsations are closely related. Aims. To discuss the wind properties variability evolved B-type stars, we derive new parameters for sample 19 Galactic BSGs by fitting theoretical line profiles H, He, Si to...
Abstract The physical processes occurring within the inner few astronomical units of protoplanetary disks surrounding Herbig Ae stars are crucial to setting environment in which outer planet-forming disk evolves and put critical constraints on accretion planet migration. We present most complete published sample high angular resolution H - K -band observations HD 163296 190073, including 30 previously unpublished nights former 45 latter with CHARA long-baseline interferometer, addition...
The Be phenomenon is present in about 20$\%$ of the B-type stars. stars show variability on a broad range timescales, which most cases related to presence circumstellar disk variable size and structure. For this reason time resolved survey highly desirable order understand mechanisms formation are still poorly understood. In addition, complete observational sample would improve statistical significance study stellar parameters. "Be Stars Observation Survey" (BeSOS) containing reduced spectra...
B[e] stars are hot surrounded by circumstellar gas and dust responsible for the presence of emission lines IR-excess in their spectra. How can be formed this highly illuminated diluted environment remains an open issue. HD 62623 is one very few A-type supergiants showing phenomenon. We obtained nine calibrated visibility measurements using VLTI/MIDI instrument SCI-PHOT mode PRISM spectral dispersion with projected baselines ranging from 13 to 71 m various position angles. used geometrical...
Be stars are rapid rotators surrounded by a gaseous disk envelope whose origin is still under debate. This responsible for observed emission lines and large infrared excess. To progress in the understanding of physical processes involved formation, we estimate parameters sample search correlations between these stellar properties. We performed spectro-interferometric observations 26 region Br$γ$ line to study kinematical properties their disks through Doppler effect. Observations were at...
Abstract The circumstellar disk density distributions for a sample of 63 Be southern stars from the BeSOS survey were found by modeling their H α emission line profiles. These densities used to compute masses and angular momenta sample. Average values mass are 3.4 × 10 −9 9.5 −10 M ⋆ early (B0–B3) late (B4–B9) spectral types, respectively. We also find that range momentum relative star is (150–200) J / (100–150) , again early- late-type stars, different between at 1% level significance....
Aims.We report the theoretical spectral energy distributions (SEDs), Brγ line profiles, and visibilities for two scenarios that can explain disk dissipation of active hot stars account transition from Be to B spectroscopic phase.
Context. As is the case of several other Be stars, Achernar surrounded by an envelope, recently detected near-IR interferometry.
Variable B supergiants (BSGs) constitute a heterogeneous group of stars with complex photometric and spectroscopic behaviours. They exhibit mass-loss variations experience different types oscillation modes, there is growing evidence that variable stellar winds photospheric pulsations are closely related. To discuss the wind properties variability evolved B-type stars, we derive new parameters for sample 19 Galactic BSGs by fitting theoretical line profiles H, He, Si to observed ones compare...
V1247 Orionis harbours a pre-transitional disc with partially cleared gap. Earlier interferometric and polarimetric observations revealed strong asymmetries both in the gap region outer disc. The presence of companion was inferred to explain these asymmetric structures ongoing clearing. Using an extensive set multi-wavelength multi-epoch we aimed identify origin previously detected asymmetries. We have observed Ori at three epochs spanning $\sim678$ days using sparse aperture masking...
TYC 8241 2652 1 is a young star that showed strong mid-infrared (mid-IR, 8-25 mu) excess in all observations before 2008 consistent with dusty disk. Between and 2010 the mid-IR luminosity of this system dropped dramatically by at least factor 30 suggesting loss dust mass an order magnitude or more. We aim to constrain possible models including removal disk material stellar activity processes, presence binary companion, other explanations suggested literature. present new X-ray observations,...
Active hot stars are (Teff ≥ 8000 K) exhibiting emission lines (namely hydrogen lines) and IR excess which both originate in a circumstellar environment. In this paper we present details the SIMECA (SImulation pour Etoiles Chaudes Actives) code is only freely available to model gaseous environment of active stars. It computes line profiles, Spectral Energy Distributions (SED) intensity maps, can be directly compared high angular resolution observations.