A5087910918- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Adaptive optics and wavefront sensing
- Geophysics and Gravity Measurements
- SAS software applications and methods
- Astrophysical Phenomena and Observations
- High-pressure geophysics and materials
- Nuclear physics research studies
- Pulsars and Gravitational Waves Research
- Planetary Science and Exploration
- Spacecraft and Cryogenic Technologies
- Quantum, superfluid, helium dynamics
- Scientific Research and Discoveries
- Spectroscopy and Chemometric Analyses
- Calibration and Measurement Techniques
- Geological and Geochemical Analysis
- Inertial Sensor and Navigation
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
Institute of Astronomy
2010-2024
KU Leuven
2007-2024
European Southern Observatory
2015
Institut d'Astrophysique Spatiale
2009
Université Paris-Saclay
2009
University of British Columbia
2009
University of Vienna
2009
University of Birmingham
2009
Thüringer Landessternwarte Tautenburg
2009
Université Paris Cité
2009
We combine results from interferometry, asteroseismology and spectroscopy to determine accurate fundamental parameters of 23 bright solar-type stars, spectral type F5 K2 luminosity classes III–V. For some stars we can use direct techniques the mass, radius, effective temperature, compare with indirect methods that rely on photometric calibrations or spectroscopic analyses. asteroseismic information available in literature infer an mass accuracy 4–15 per cent. From radius 3 find evidence...
Asteroseismology Delivers Using asteroseismology—the study of stellar oscillations, it is possible to probe the interior stars and derive parameters, such as mass radius (see Perspective by Montgomery ). Based on asteroseismic data from NASA Kepler mission, Chaplin et al. (p. 213 ) detected solarlike oscillations in 500 solartype our Galaxy. The distribution radii these matches that expected evolution theory, but does not, which challenges knowledge star formation rates, forming stars,...
<i>Context. <i/>Observations and analysis of solar-type oscillations in red-giant stars is an emerging aspect asteroseismic with a number open questions yet to be explored. Although stochastic have previously been detected red giants from both radial velocity photometric measurements, those data were either too short or had sampling that was not complete enough perform detailed the variability. The quality quantity as provided by CoRoT satellite necessary provide breakthrough observing...
établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics privés.
We present the CoRoT light curve of Beta Cep star HD 180642, assembled during first long run space mission, as well archival single-band photometry. Our goal is to analyse detailed behaviour in and interpret it terms excited mode frequencies. After describing noise properties detail, we use various time series analysis fitting techniques model curve, for physical assumptions. apply statistical goodness-of-fit criteria that allow us select most appropriate fit data. conclude based on...
We have observed oscillations in the nearby G2 subgiant star beta Hyi using high-precision velocity observations obtained over more than a week with HARPS and UCLES spectrographs. The oscillation frequencies show regular comb structure, as expected for solar-like oscillations, but several l=1 modes being strongly affected by avoided crossings. data, combined those we five years earlier, allow us to identify 28 modes. By scaling large frequency separation from Sun, measure mean density of an...
Context. Asteroid modeling efforts in the last decade resulted a comprehensive dataset of almost 400 convex shape models and their rotation states. These already provided deep insight into physical properties main-belt asteroids or large collisional families. Going finer detail (e.g., smaller families, with sizes ≲20 km) requires knowledge parameters more objects.
Using the oscillation frequencies of alpha Cen A recently discovered by Bouchy & Carrier, available astrometric, photometric and spectroscopic data, we tried to improve calibration visual binary system Cen. With revisited masses Pourbaix et al. (2002) do not succeed obtain a solution satisfying all seismic observational constraints. Relaxing constraints on masses, have found an age t_alpha Cen=4850+-500 Myr, initial helium mass fraction Y_i = 0.300+-0.008, metallicity (Z/X)_i=0.0459+-0.0019,...
We have made a clear detection of excess power, providing strong evidence for solar-like oscillations in the G2 subgiant beta Hyi. observed this star over five nights with UCLES echelle spectrograph on 3.9-m Anglo-Australian Telescope, using an iodine absorption cell as velocity reference. The time series 1196 measurements shows rms scatter 3.30 m/s, and mean noise level amplitude spectrum at frequencies above 0.5 mHz is 0.11 m/s. see power centred 1.0 mHz, peak amplitudes about agreement...
This paper presents the analysis of Doppler p-mode observations G2V star α Cen A obtained with spectrograph CORALIE in May 2001. Thirteen nights have made it possible to collect 1850 radial velocity measurements a standard deviation about 1.5 m s-1. Twenty-eight oscillation modes been identified power spectrum between 1.8 and 2.9 mHz amplitudes range 12 44 cm The average large small spacing are respectively equal 105.5 5.6 μHz. comparison stellar models is presented.
We present the discovery of solar-like oscillations in time-series G9.5 red giant ε Ophiuchi. The data were obtained with CORALIE spectrograph at 1.2 m Swiss telescope La Silla and ELODIE 1.93 Observatoire de Haute Provence. Periodic variations can be observed radial velocity time series individual nights. In power spectrum there is a clear excess around 60 μHz, several oscillation frequencies distinguished. Our auto-correlation comb response analysis reveals large separation either 4.8 μHz...
We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting weights allows us suppress sidelobes power spectrum. Stacking spectrum so-called echelle diagram reveals two clear ridges identify even and odd values angular degree (l=0 2, l=1 3, respectively). interpret strong, narrow peak at 446 muHz lies close ridge as mode...
We have made a clear detection of p-mode oscillations in the nearest solar-like G2V star $\alpha$ Cen A with CORALIE spectrograph on 1.2-m Swiss telescope at ESO La Silla Observatory. report 5 nights observation this May 2001 during which 1260 high precision radial velocity measurements were obtained. The power spectrum clearly shows several identifiable peaks between 1.7 and 3 mHz. average large splitting 105.7 $\mu$Hz amplitude about 35 cm s$^{-1}$ these modes are agreement theoretical...
Detailed models of α Cen A and B based on new seismological data for by Carrier & Bourban ([CITE]) have been computed using the Geneva evolution code including atomic diffusion. Taking into account numerous observational constraints now available system, we find a stellar model which is in good agreement with astrometric, photometric, spectroscopic asteroseismic data. The global parameters system are firmly constrained to an age Gyr, initial helium mass fraction metallicity . Thanks these...
We present new orbits for sixteen Ap spectroscopic binaries, four of which might in fact be Am stars, and give their orbital elements. Four them are SB2 systems: HD 5550, 22128, 56495 98088. The twelve other stars are: 9996, 12288, 40711, 54908, 65339, 73709, 105680, 138426, 184471, 188854, 200405 216533. Rough estimates the individual masses components 65339 (53 Cam) given, combining our radial velocities with results speckle interferometry Hipparcos parallaxes. Considering mass functions...
Several attempts have been made to detect solar-like oscillations in the G0 IV star η Boo. We present here new observations on this simultaneously conducted with two spectrographs: Coralie mounted 1.2-m Swiss telescope at ESO La Silla Observatory (Chile) and Elodie based 1.93-m Observatoire de Haute-Provence (France). In total, 1239 spectra were collected over 13 nights. The power spectrum of high precision velocity time series clearly presents several identifiable peaks between 0.4 1.0 mHz...
<i>Context. <i/>Observations of solar-like oscillations obtained either from the ground or space stimulated study effects various physical processes on modelling solar-type stars.<i>Aims. <i/>The influence rotational mixing evolution and asteroseismic properties stars is studied.<i>Methods. <i/>Global models computed with without a comprehensive treatment shellular rotation are compared. The internal magnetic fields also discussed in framework Tayler-Spruit dynamo.<i>Results. <i/>Rotational...
Convection in red giant stars excites resonant acoustic waves whose frequencies depend on the sound speed inside star, which turn depends properties of stellar interior. Therefore, asteroseismology is most robust available method for probing internal structure stars. Solar-like oscillations HR7349 are investigated. Our study based a time series 380760 photometric measurements spread over 5 months obtained with CoRoT satellite. Mode parameters were estimated using maximum likelihood...
A precise characterisation of the red giants in seismology fields CoRoT satellite is a prerequisite for further in-depth seismic modelling. High-resolution FEROS and HARPS spectra were obtained as part ground-based follow-up campaigns 19 targets holding great asteroseismic potential. These data are used to accurately estimate their fundamental parameters abundances 16 chemical species self-consistent manner. Some powerful probes mixing investigated (the Li CNO abundances, well carbon...
Abstract We have detected solar-like oscillations in the mid-K-dwarf ϵ Indi A, making it coolest dwarf to measured oscillations. The star is noteworthy for harboring a pair of brown companions and Jupiter-type planet. observed A during two radial velocity campaigns, using high-resolution spectrographs HARPS (2011) UVES (2021). Weighting time series, we computed power spectra established detection with excess located at 5265 ± 110 μ Hz—the highest frequency so far any star. measurement center...