Results for "C. Aerts"

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The pulsations and potential for seismology of B starsNov 13 2006We review the nature of the oscillations of main-sequence and supergiant stars of spectral type B. Seismic tuning of the interior structure parameters of the $\beta $Cep stars has been achieved since three years. The results are based on frequencies derived ... More
Comparative clustering analysis of variable stars in the Hipparcos, OGLE Large Magellanic Cloud and CoRoT exoplanet databasesJun 01 2009Context. Discovery of new variability classes in large surveys using multivariate statistics techniques such as clustering, relies heavily on the correct understanding of the distribution of known classes as point processes in parameter space. Aims. Our ... More
Asteroseismic versus Gaia distances: a first comparisonSep 28 2016Oct 12 2016Context. The Kepler space mission led to a large amount of high-precision time series of solar-like oscillators. Using a Bayesian analysis that combines asteroseismic techniques and additional ground-based observations, the mass, radius, luminosity, and ... More
Seismic modelling of the $β\,$Cep star HD\,180642 (V1449\,Aql)Sep 04 2011We present modelling of the $\beta\,$Cep star HD\,180642 based on its observational properties deduced from CoRoT and ground-based photometry as well as from time-resolved spectroscopy. We investigate whether present-day state-of-the-art models are able ... More
Tidally induced radial-velocity variations in close binariesJan 04 2002A theoretical framework for the determination of tidally induced radial-velocity variations in a component of a close binary is presented. Both the free and the forced oscillations of the component are treated as linear, isentropic perturbations of a ... More
Line-profile variations of stochastically excited oscillations in four evolved starsFeb 10 2010Since solar-like oscillations were first detected in red-giant stars, the presence of non-radial oscillation modes has been debated. Spectroscopic line-profile analysis was used in the first attempt to perform mode identification, which revealed that ... More
Asteroseismology and Oblique Pulsator Model of Beta CepheiJan 21 2000We discuss the oscillation features of Beta Cephei, which is a magnetic star in which the magnetic axis seems to be oblique to the rotation axis. We interpret the observed equi-distant fine structures of the frequency spectrum as a manifestation of a ... More
Experimental Evidence for Quantum Structure in CognitionOct 29 2008Jan 22 2009We proof a theorem that shows that a collection of experimental data of membership weights of items with respect to a pair of concepts and its conjunction cannot be modeled within a classical measure theoretic weight structure in case the experimental ... More
A Cross-disciplinary Framework for the Description of Contextually Mediated ChangeJun 01 2007We present a mathematical framework (referred to as Context-driven Actualization of Potential, or CAP) for describing how entities change over time under the influence of a context. The approach facilitates comparison of change of state of entities studied ... More
Evolution as context-driven actualization of potential: Toward an interdisciplinary theory of change of stateNov 05 2005It is increasingly evident that there is more to biological evolution than natural selection; moreover, the concept of evolution is not limited to biology. We propose an integrative framework for characterizing how entities evolve, in which evolution ... More
The Heart of an Image: Quantum Superposition and Entanglement in Visual PerceptionJan 31 2018We analyse the way in which the principle that 'the whole is greater than the sum of its parts' manifests itself with phenomena of visual perception. For this investigation we use insights and techniques coming from quantum cognition, and more specifically ... More
Observational signatures of convectively driven waves in massive starsMay 25 2015May 30 2015We demonstrate observational evidence for the occurrence of convectively driven internal gravity waves (IGW) in young massive O-type stars observed with high-precision CoRoT space photometry. This evidence results from a comparison between velocity spectra ... More
Asteroseismic modelling of the two F-type hybrid pulsators KIC10080943A and KIC10080943BMay 25 2016Jun 08 2016Pulsating binary stars are ideal targets for testing the theory of stellar structure and evolution. Fundamental parameters can be derived to high precision from binary modelling and provide crucial constraints for seismic modelling. High-order gravity ... More
The early-type close binary CV Velorum revisitedJan 25 2007Our goal was to improve the fundamental parameters of the massive close double-lined eclipsing B2.5V+B2.5V binary CV Velorum.We gathered new high-resolution echelle spectroscopy on 13 almost consecutive nights covering essentially two orbits. We computed ... More
Abundance analysis of prime B-type targets for asteroseismology II. B6--B9.5 stars in the field of view of the CoRoTJun 26 2009The CoRoT satellite is collecting precise time-resolved photometry for tens of asteroseismology targets. To ensure a correct interpretation of the CoRoT data, the atmospheric parameters, chemical compositions, and rotational velocities of the stars must ... More
Statistical properties of a sample of periodically variable B-type supergiants - Evidence for opacity-driven gravity-mode oscillationsNov 15 2006We have studied a sample of 28 periodically variable B-type supergiants selected from the HIPPARCOS mission and 12 comparison stars covering the whole B-type spectral range. Our goal is to test if their variability is compatible with opacity-driven non-radial ... More
A spectroscopic study of southern (candidate) gamma Doradus stars. II. Detailed abundance analysis and fundamental parametersNov 24 2007The gamma Doradus stars are a recent class of variable main sequence F-type stars located on the red edge of the Cepheid instability strip. They pulsate in gravity modes, and this makes them particularly interesting for detailed asteroseismic analysis, ... More
A Grid of FASTWIND NLTE Model Atmospheres of Massive StarsSep 22 2006In the last few years our knowledge of the physics of massive stars has improved tremendously. However, further investigations are still needed, especially regarding accurate calibrations of their fundamental parameters. To this end, we have constructed ... More
The interior angular momentum of core hydrogen burning stars from gravity-mode oscillationsSep 06 2017A major uncertainty in the theory of stellar evolution is the angular momentum distribution inside stars and its change during stellar life. We compose a sample of 67 stars in the core-hydrogen burning phase with a $\log\,g$ value from high-resolution ... More
Searching for Line Profile Variability in HgMn StarsOct 18 2002Spectra of four non-magnetic chemically peculiar late B type stars (HgMn) stars are analysed to detect periodic spectral line variations (LPVs). A procedure developed to study LPVs in Slowly Pulsating B stars has been adopted as pulsational properties ... More
The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacingsJul 04 2016Jul 17 2016CONTEXT. Gamma Doradus stars (hereafter gamma Dor stars) are known to exhibit gravity- and/or gravito-intertial modes that probe the inner stellar region near the convective core boundary. The non-equidistant spacing of the pulsation periods is an observational ... More
A Quantum Model for the Ellsberg and Machina ParadoxesAug 11 2012The Ellsberg and Machina paradoxes reveal that expected utility theory is problematical when real subjects take decisions under uncertainty. Suitable generalizations of expected utility exist which attempt to solve the Ellsberg paradox, but none of them ... More
Fourier transforms on Cantor sets: A study in non-Diophantine arithmetic and calculusMar 17 2016Fractals equipped with intrinsic arithmetic lead to a natural definition of differentiation, integration and complex numbers. Applying the formalism to the problem of a Fourier transform on fractals we show that the resulting transform has all the expected ... More
A Case for Applying an Abstracted Quantum Formalism to CognitionApr 11 2004This chapter outlines some of the highlights of efforts undertaken by our group to describe the role of contextuality in the conceptualization of conscious experience using generalized formalisms from quantum mechanics.
Simple fractal calculus from fractal arithmeticJun 04 2016May 23 2018Non-Newtonian calculus that starts with elementary non-Diophantine arithmetic operations of a Burgin type is applicable to all fractals whose cardinality is continuum. The resulting definitions of derivatives and integrals are simpler from what one finds ... More
The Liar-paradox in a Quantum Mechanical PerspectiveJul 16 2000In this paper we concentrate on the nature of the liar paradox as a cognitive entity; a consistently testable configuration of properties. We elaborate further on a quantum mechanical model [Aerts, Broekaert, Smets 1999] that has been proposed to analyze ... More
Abundance analysis of prime B-type targets for asteroseismology I. Nitrogen excess in slowly-rotating beta Cephei starsJul 12 2006We present the results of a detailed NLTE abundance study of nine beta Cephei stars, all of them being prime targets for theoretical modelling: gamma Peg, delta Cet, nu Eri, beta CMa, xi1 CMa, V836 Cen, V2052 Oph, beta Cep and DD (12) Lac. The following ... More
Pulsating B-type stars in the open cluster NGC 884: frequencies, mode identification and asteroseismologyJul 16 2013Recent progress in the seismic interpretation of field beta Cep stars has resulted in improvements of the physics in the stellar structure and evolution models of massive stars. Further asteroseismic constraints can be obtained from studying ensembles ... More
A line profile analysis of the pulsating red giant star epsilon Ophiuchi (G9.5III)Sep 01 2006So far, solar-like oscillations have been studied using radial velocity and/or light curve variations, which reveal frequencies of the oscillation modes. Line-profile variations, however, are also a valuable diagnostic to characterise radial and non-radial ... More
High-precision elements of double-lined spectroscopic binaries from combined interferometry and spectroscopy. Application to the beta Cephei star beta CentauriMay 09 2006We present methodology to derive high-precision estimates of the fundamental parameters of double-lined spectroscopic binaries. We apply the methods to the case study of the double-lined beta Cephei star beta Centauri. We also present a detailed analysis ... More
An observational asteroseismic study of the pulsating B-stars in the open cluster NGC 884Oct 01 2013Recent progress in the seismic interpretation of field {\beta} Cep stars has resulted in improvements of the physical description in the stellar structure and evolution model computations of massive stars. Further asteroseismic constraints can be obtained ... More
A recent history of science cases for interferometryJan 12 2018Optical long-baseline interferometry is a unique and powerful technique for astronomical research. Since 2004, optical interferometers have produced an increasing number of scientific papers covering various fields of astrophysics. As current interferometric ... More
An asteroseismic study of the Beta Cephei star Theta Ophiuchi: spectroscopic resultsJun 27 2005We present the results of a detailed analysis of 121 ground-based high-resolution high S/N spectroscopic measurements spread over 3 years for the Beta Cephei star Theta Ophiuchi. We discovered Theta Oph to be a triple system. In addition to the already ... More
Asteroseismology of eclipsing binary stars using Kepler and the HERMES spectrographJan 30 2014We introduce our PhD project in which we focus on pulsating stars in eclipsing binaries. The combination of high-precision Kepler photometry with high-resolution HERMES spectroscopy allows for detailed descriptions of our sample of target stars. We report ... More
Automated classification of periodic variable stars{Improved methodology for the automated classification of periodic variable stars}Jan 26 2011We present a novel automated methodology to detect and classify periodic variable stars in a large database of photometric time series. The methods are based on multivariate Bayesian statistics and use a multi-stage approach. We applied our method to ... More
Estimating Stellar Parameters from Spectra using a Hierarchical Bayesian ApproachJan 16 2007A method is developed for fitting theoretically predicted astronomical spectra to an observed spectrum. Using a hierarchical Bayesian principle, the method takes both systematic and statistical measurement errors into account, which has not been done ... More
On the use of the Fourier Transform to determine the projected rotational velocity of line-profile variable B starsJul 24 2014The Fourier Transform method is a popular tool to derive the rotational velocities of stars from their spectral line profiles. However, its domain of validity does not include line-profile variables with time-dependent profiles. We investigate the performance ... More
Pulsations detected in the line profile variations of red giants: Modelling of line moments, line bisector and line shapeAug 21 2006Contents: So far, red giant oscillations have been studied from radial velocity and/or light curve variations, which reveal frequencies of the oscillation modes. To characterise radial and non-radial oscillations, line profile variations are a valuable ... More
The Current Status of AsteroseismologyMar 25 2008Stellar evolution, a fundamental bedrock of modern astrophysics, is driven by the physical processes in stellar interiors. While we understand these processes in general terms, we lack some important ingredients. Seemingly small uncertainties in the input ... More
Asteroseismic versus Gaia distances: a first comparisonSep 28 2016Oct 18 2016Context. The Kepler space mission led to a large amount of high-precision time series of solar-like oscillators. Using a Bayesian analysis that combines asteroseismic techniques and additional ground-based observations, the mass, radius, luminosity, and ... More
delta Ceti is not monoperiodic: seismic modeling of a beta Cephei star from MOST spacebased photometryFeb 02 2006The beta Cephei star delta Ceti was considered one of the few monoperiodic variables in the class. Despite (or perhaps because of) its apparently simple oscillation spectrum, it has been challenging and controversial to identify this star's pulsation ... More
Automated supervised classification of variable stars II. Application to the OGLE databaseJun 20 2008We aim to extend and test the classifiers presented in a previous work against an independent dataset. We complement the assessment of the validity of the classifiers by applying them to the set of OGLE light curves treated as variable objects of unknown ... More
The orbit of the close spectroscopic binary epsilon Lupi and the intrinsic variability of its early B-type componentsJul 15 2005We subjected 106 new high-resolution spectra of the double-lined spectroscopic close binary epsilon Lupi, obtained in a time-span of 17 days from two different observatories, to a detailed study of orbital and intrinsic variations. We derived accurate ... More
Collective pulsational velocity broadening due to gravity modes as a physical explanation for macroturbulence in hot massive starsSep 19 2009We aimed at finding a physical explanation for the occurrence of macroturbulence in the atmospheres of hot massive stars, a phenomenon found in observations since more than a decade but yet unexplained. We computed time series of line profiles for evolved ... More
On the origin of macroturbulence in hot starsDec 14 2008Since the use of high-resolution high signal-to-noise spectroscopy in the study of massive stars, it became clear that an ad-hoc velocity field at the stellar surface, termed macroturbulence, is needed to bring the observed shape of spectral lines into ... More
Asteroseismic versus Gaia distances: a first comparisonSep 28 2016Context. The Kepler space mission led to a large amount of high-precision time series of solar-like oscillators. Using a Bayesian analysis that combines asteroseismic techniques and additional ground-based observations, the mass, radius, luminosity, and ... More
Global stellar variability study in the field-of-view of the Kepler satelliteFeb 11 2011We present the results of an automated variability analysis of the Kepler public data measured in the first quarter (Q1) of the mission. In total, about 150 000 light curves have been analysed to detect stellar variability, and to identify new members ... More
Interpreting Quantum Particles as Conceptual EntitiesApr 15 2010We elaborate an interpretation of quantum physics founded on the hypothesis that quantum particles are conceptual entities playing the role of communication vehicles between material entities composed of ordinary matter which function as memory structures ... More
Relativity Theory RefoundedNov 27 2015We put forward a new view of relativity theory that makes the existence of a flow of time compatible with the four-dimensional block universe. To this end, we apply the creation-discovery view elaborated for quantum mechanics to relativity theory and ... More
Quantum Theory and Human Perception of the Macro-WorldMar 17 2014May 29 2014We investigate the question of 'why customary macroscopic entities appear to us humans as they do, i.e. as bounded entities occupying space and persisting through time', starting from our knowledge of quantum theory, how it affects the behavior of such ... More
The Age and Interior Rotation of Stars from AsteroseismologyMar 23 2015Apr 10 2015We provide a status report on the determination of stellar ages from asteroseismology for stars of various masses and evolutionary stages. The ability to deduce the ages of stars with a relative precision of typically 10 to 20% is a unique opportunity ... More
Massive Star Asteroseismology in ActionJul 24 2014After highlighting the principle and power of asteroseismology for stellar physics, we briefly emphasize some recent progress in this research for various types of stars. We give an overview of high-precision high duty-cycle space photometry of OB-type ... More
Quantum and classical probability as Bayes-optimal observationJan 20 2006We propose a simple abstract formalisation of the act of observation, in which the system and the observer are assumed to be in a pure state and their interaction deterministically changes the states such that the outcome can be read from the state of ... More
Spin and Wind Directions II: A Bell State Quantum ModelJun 05 2017In the first half of this two-part article, we analyzed a cognitive psychology experiment where participants were asked to select pairs of directions that they considered to be the best example of 'Two Different Wind Directions', and showed that the data ... More
Asteroseismology of binary stars and a compilation of core overshoot and rotational frequency values of OB starsNov 25 2013After a brief introduction into the asteroseismic modelling of stars, we provide a compilation of the current seismic estimates of the core overshooting parameter and of the rotational frequency of single and binary massive stars. These important stellar ... More
Undecidable classical properties of observersJun 30 2005A property of a system is called actual, if the observation of the test that pertains to that property, yields an affirmation with certainty. We formalize the act of observation by assuming that the outcome correlates with the state of the observed system ... More
A realistic device that simulates the non-local PR box without communicationApr 22 2005Apr 26 2005A black box with two input bits and two output bits is called a non-local PR box, if the XOR of the output bits equals the AND of the input bits. In a recent article, Cerf et al. show that Alice and Bob, using such a PR box, can effectively simulate entanglement ... More
Asteroseismology of close binary starsJan 16 2007In this review paper, we summarise the goals of asteroseismic studies of close binary stars. We first briefly recall the basic principles of asteroseismology, and highlight how the binarity of a star can be an asset, but also a complication, for the interpretation ... More
K2 space photometry reveals rotational modulation and stellar pulsations in chemically peculiar A and B starsMay 04 2018May 11 2018The physics of magnetic hot stars and how a large-scale magnetic field affects their interior properties is largely unknown. Few studies have combined high-quality observations and modelling of magnetic pulsating stars, known as magneto-asteroseismology, ... More
Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal componentsMar 13 2019Context. Stellar magnetic fields are one of the candidates often invoked to explain the missing transport of angular momentum observed in the models of stellar interiors. However, the properties of an internal magnetic field and the consequences of its ... More
Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal componentsMar 13 2019May 15 2019Context. Stellar magnetic fields are one of the candidates often invoked to explain the missing transport of angular momentum observed in the models of stellar interiors. However, the properties of an internal magnetic field and the consequences of its ... More
The PLATO End-to-End CCD Simulator -- Modelling space-based ultra-high precision CCD photometry for the assessment study of the PLATO MissionApr 05 2010The PLATO satellite mission project is a next generation ESA Cosmic Vision satellite project dedicated to the detection of exo-planets and to asteroseismology of their host-stars using ultra-high precision photometry. The main goal of the PLATO mission ... More
Interferometry and spectroscopy of Beta Cen: a Beta Cephei star in a binary systemSep 12 1998Sep 15 1998Beta Cen is a bright Beta Cephei variable and has long been suspected to be a binary. Here we report interferometric observations with the 3.9-m Anglo-Australian Telescope at a single epoch which show the star to be a binary with components separated ... More
Is macroturbulent broadening in OB Supergiants related to pulsations?Apr 14 2010Apr 20 2010The spectrum of O and B Supergiants is known to be affected by an important extra line-broadening (usually called macroturbulence) that adds to stellar rotation. Recent analysis of high resolution spectra has shown that the interpretation of this line-broadening ... More
The ASTROID Simulator Software Package: Realistic Modelling of High-Precision High-Cadence Space-Based ImagingFeb 11 2014The preparation of a space-mission that carries out any kind of imaging to detect high-precision low-amplitude variability of its targets requires a robust model for the expected performance of its instruments. This model cannot be derived from simple ... More
Macroturbulent broadening: a single snap-shot approach to investigate pulsations in massive stars?Nov 05 2011We present a brief progress report of our project aimed at the investigation of the so-called macroturbulent broadening affecting the line-profiles of O and early B-type stars, and speculate about the possible use of this spectroscopic feature as a single ... More
Spectroscopic determination of the fundamental parameters of 66 B-type stars in the field-of-view of the CoRoT satelliteOct 15 2009We aim to determine the fundamental parameters of a sample of B stars with apparent visual magnitudes below 8 in the field-of-view of the CoRoT space mission, from high-resolution spectroscopy. We developed an automatic procedure for the spectroscopic ... More
Is macroturbulence in OB Sgs related to pulsations?Sep 20 2010As part of a long term observational project, we are investigating the macroturbulent broadening in O and B supergiants (Sgs) and its possible connection with spectroscopic variability phenomena and stellar oscillations. We present the first results of ... More
Observational evidence for a correlation between macroturbulent broadening and line-profile variations in OB SupergiantsAug 04 2010The spectra of O and B supergiants are known to be affected by a significant form of extra line broadening (usually referred to as macroturbulence) in addition to that produced by stellar rotation. Recent analyses of high resolution spectra have shown ... More
The shape of convective core overshooting from gravity-mode period spacingsFeb 06 2018The evolution of stars born with a convective core is highly dependent on the efficiency and extent of near core mixing processes, which effectively increases both the core mass and main-sequence lifetime. We investigate to what extent gravity-mode period ... More
Radial velocities of giant stars: an investigation of line profile variationsOct 22 2007Since 1999, a radial velocity survey of 179 red giant stars is ongoing at Lick Observatory with a one month cadence. At present ~20-100 measurements have been collected per star with an accuracy of 5 to 8 m/s. Of the stars monitored, 145 (80%) show radial ... More
The Spintronic Properties of Rare Earth NitridesAug 18 2003The electronic structure of the rare earth nitrides is studied systematically using the {\it ab-initio} self-interaction corrected local-spin-density approximation (SIC-LSD). This approach allows both a localised description of the rare earth $f-$electrons ... More
On the co-existence of chemically peculiar Bp stars, slowly pulsating B stars and constant B stars in the same part of the H-R diagramFeb 05 2007Aims. In order to better model massive B-type stars, we need to understand the physical processes taking place in slowly pulsating B (SPB) stars, chemically peculiar Bp stars, and non-pulsating normal B stars co-existing in the same part of the H-R diagram. ... More
High-Precision Spectroscopy of Pulsating StarsJan 16 2007We review methodologies currently available to interprete time series of high-resolution high-S/N spectroscopic data of pulsating stars in terms of the kind of (non-radial) modes that are excited. We illustrate the drastic improvement of the detection ... More
Simulating stochastically excited oscillations. The mode lifetime of xi HyaJan 16 2004The discovery of solar-like oscillations in the giant star xy Hya (G7III) was reported by Frandsen et al. (2002). Their frequency analysis was very limited due to alias problems in the data set (caused by single-site observations). The extent to which ... More
Denoising spectroscopic data by means of the improved Least-Squares Deconvolution methodOct 11 2013The MOST, CoRoT, and Kepler space missions led to the discovery of a large number of intriguing, and in some cases unique, objects among which are pulsating stars, stars hosting exoplanets, binaries, etc. Although the space missions deliver photometric ... More
The observation of Delta Sct and Gamma Dor stars by using MONS satelliteMar 23 2000The MONS space experiment will be able to verify some of the most important topics in the asteroseismologic studies of Delta Sct and Gamma Dor stars. We discuss how the $\gamma$ Doradus can be considered possible "bridges" between the opacity driven overstable ... More
A gamma Doradus star campaignNov 27 2001We report on the results from a large photometric campaign on thirty five gamma Dor star candidates undertaken at the Institute of Astronomy of the University of Leuven in the framework of the Flanders -- South-Africa grant. An overview of the data, as ... More
KIC 10526294: a slowly rotating B star with rotationally split, quasi-equally spaced gravity modesJul 10 2014Jul 24 2014Massive stars are important for the chemical enrichment of the universe. Since internal mixing processes influence their lives, it is very important to place constraints on the corresponding physical parameters, such as core overshooting and the internal ... More
Automated supervised classification of variable stars I. MethodologyNov 05 2007The fast classification of new variable stars is an important step in making them available for further research. Selection of science targets from large databases is much more efficient if they have been classified first. Defining the classes in terms ... More
Diverse Variability of O and B Stars Revealed from 2-minute Cadence Light Curves in Sectors 1 and 2 of the TESS Mission: Selection of an Asteroseismic SampleJan 22 2019Jan 24 2019Uncertainties in stellar structure and evolution theory are largest for stars undergoing core convection on the main sequence. A powerful way to calibrate the free parameters used in the theory of stellar interiors is asteroseismology, which provides ... More
Discovery of magnetic fields in the beta Cephei star xi^1 CMa and in several Slowly Pulsating B starsApr 12 2006We present the results of a magnetic survey of a sample of eight beta Cephei stars and 26 Slowly Pulsating B stars with FORS1 at the VLT. A weak mean longitudinal magnetic field of the order of a few hundred Gauss is detected in the beta Cephei star xi^1 ... More
An evolutionary study of the pulsating subdwarf B eclipsing binary PG1336-018 (NY Vir)Aug 01 2007The formation of subdwarf B (sdB) stars is not well understood within the current framework of stellar single and binary evolution. In this study, we focus on the formation and evolution of the pulsating sdB star in the very short-period eclipsing binary ... More
Precise radial velocities of giant stars. IV. A correlation between surface gravity and radial velocity variation and a statistical investigation of companion propertiesJan 04 2008Since 1999, we have been conducting a radial velocity survey of 179 K giants using the CAT at UCO/Lick observatory. At present ~20-100 measurements have been collected per star with a precision of 5 to 8 m/s. Of the stars monitored, 145 (80%) show radial ... More
Forward seismic modelling of the pulsating magnetic B-type star HD 43317May 02 2018May 31 2018The large-scale magnetic fields detected at the surface of about 10% of hot stars extend into the stellar interior, where they may alter the structure. Deep inner regions of stars are only observable using asteroseismology. Here, we investigated the pulsating ... More
Eclipsing binaries with pulsating components: CoRoT 102918586Apr 09 2010We present the preliminary results of the study of an interesting target in the first CoRoT exo-planet field (IRa1): CoRoT 102918586. Its light curve presents additional variability on the top of the eclipses, whose pattern suggests multi- frequency pulsations. ... More
Necessity of Combining Mutually Incompatible Perspectives in the Construction of a Global View: Quantum Probability and Signal AnalysisMar 11 2005Mar 12 2005The scientific fields of quantum mechanics and signal-analysis originated within different settings, aimed at different goals and started from different scientific paradigms. Yet the development of the two subjects has become increasingly intertwined. ... More
Discovery of a red giant with solar-like oscillations in an eclipsing binary system from Kepler space-based photometryJan 03 2010Oscillating stars in binary systems are among the most interesting stellar laboratories, as these can provide information on the stellar parameters and stellar internal structures. Here we present a red giant with solar-like oscillations in an eclipsing ... More
The binary properties of the pulsating subdwarf B eclipsing binary PG 1336-018 (NY Vir)Jun 22 2007We present an unbiased orbit solution and mass determination of the components of the eclipsing binary NY Vir as a critical test for the formation scenarios of subdwarf B stars. We obtained high-resolution time series VLT/UVES spectra and high-speed multicolour ... More
Binary Asteroseismic Modelling: isochrone-cloud methodology and application to Kepler gravity-mode pulsatorsOct 01 2018The simultaneous presence of variability due to both pulsations and binarity is no rare phenomenon. Unfortunately, the complexities of dealing with even one of these sources of variability individually means that the other signal is often treated as a ... More
Magnetic characterization and variability study of the magnetic SPB star o LupAug 16 2018Thanks to large dedicated surveys, large-scale magnetic fields have been detected for about 10% of early-type stars. We aim to precisely characterize the large-scale magnetic field of the magnetic component of the wide binary $o$ Lup, by using high-resolution ... More
Detection of magnetic fields in chemically peculiar stars observed with the K2 space missionMay 02 2018We report the results of an observational study aimed at searching for magnetic pulsating hot stars suitable for magneto-asteroseismology. A sample of sixteen chemically peculiar stars was selected and analysed using both high-resolution spectropolarimetry ... More
Straight Line Triangle RepresentationsMar 24 2015A straight line triangle representation (SLTR) of a planar graph is a straight line drawing such that all the faces including the outer face have triangular shape. Such a drawing can be viewed as a tiling of a triangle using triangles with the input graph ... More
Distilling the Essence of an Evolutionary Process and Implications for a Formal Description of CultureSep 18 2013It has been proposed that, since the origin of life and the ensuing evolution of biological species, a second evolutionary process has appeared on our planet. It is the evolution of culture-e.g., ideas, beliefs, and artifacts. Does culture evolve in the ... More
Contextualizing Concepts using a Mathematical Generalization of the Quantum FormalismMay 26 2002Aug 06 2004We outline the rationale and preliminary results of using the State Context Property (SCOP) formalism, originally developed as a generalization of quantum mechanics, to describe the contextual manner in which concepts are evoked, used, and combined to ... More
A model of the emergence and evolution of integrated worldviewsJan 09 2010It is proposed that the ability of humans to flourish in diverse environments and evolve complex cultures reflects the following two underlying cognitive transitions. The transition from the coarse-grained associative memory of Homo habilis to the fine-grained ... More
State Property Systems and Closure Spaces: Extracting the Classical and Nonclassical PartsApr 12 2004We introduce classical properties using the concept of super selection rule, i.e. two properties are separated by a superselection rule iff there do not exist 'superposition states' related to these two properties. Then we show that the classical properties ... More
Deep Learning Applied to the Asteroseismic Modeling of Stars with Coherent Oscillation ModesNov 08 2018We develop a novel method based on machine learning principles to achieve optimal initiation of CPU-intensive computations for forward asteroseismic modeling in a multi-D parameter space. A deep neural network is trained on a precomputed asteroseismology ... More
A search for new gamma Doradus stars in the Geneva photometric databaseNov 02 2000We present a study of selected potential gamma Doradus stars observed in the Geneva photometric system. Eleven stars were monitored at least during the last year of functioning of the 70 cm Swiss telescope at La Silla, leading to about one thousand photometric ... More
Mode Identification of the Slowly Pulsating F0V Star V398 Aurigae (9 Aur)Sep 15 1995We have investigated the F0V star V398\,Aurigae (= 9 Aur) under the assumption that it is undergoing non-radial gravity mode oscillations and that the two principal periods given by Krisciunas et al. (1995) are correct. We find that the two periods are ... More