References of "Daszynska-Daszkiewicz, J"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 11 of 11 1 Kepler observations of the variability in B-type starsBalona, L. A.; Pigulski, A.; Cat, P De et alin Monthly Notices of the Royal Astronomical Society (2011), 413The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies, characteristic of slowly pulsating B (SPB) stars ... [more ▼]The analysis of the light curves of 48 B-type stars observed by Kepler is presented. Among these are 15 pulsating stars, all of which show low frequencies, characteristic of slowly pulsating B (SPB) stars. Seven of these stars also show a few weak, isolated high frequencies and they could be considered as SPB/β Cephei (β Cep) hybrids. In all cases, the frequency spectra are quite different from what is seen from ground-based observations. We suggest that this is because most of the low frequencies are modes of high degree which are predicted to be unstable in models of mid-B stars. We find that there are non-pulsating stars within the β Cep and SPB instability strips. Apart from the pulsating stars, we can identify stars with frequency groupings similar to what is seen in Be stars but which are not Be stars. The origin of the groupings is not clear, but may be related to rotation. We find periodic variations in other stars which we attribute to proximity effects in binary systems or possibly rotational modulation. We find no evidence for pulsating stars between the cool edge of the SPB and the hot edge of the δ Sct instability strips. None of the stars shows the broad features which can be attributed to stochastically excited modes as recently proposed. Among our sample of B stars are two chemically peculiar stars, one of which is a HgMn star showing rotational modulation in the light curve. [less ▲]Detailed reference viewed: 27 (10 ULg) Hybrid gamma Doradus-delta Scuti Pulsators: New Insights into the Physics of the Oscillations from Kepler ObservationsGrigahcène, Ahmed; Antoci, V.; Balona, L. et alin Astrophysical Journal (2010), 713Observations of the pulsations of stars can be used to infer their interior structure and test theoretical models. The main-sequence Î³ Doradus (Dor) and Î´ Scuti (Sct) stars with masses 1.2-2.5 M [SUB ... [more ▼]Observations of the pulsations of stars can be used to infer their interior structure and test theoretical models. The main-sequence Î³ Doradus (Dor) and Î´ Scuti (Sct) stars with masses 1.2-2.5 M [SUB]sun[/SUB] are particularly useful for these studies. The Î³ Dor stars pulsate in high-order g-modes with periods of order 1 day, driven by convective blocking at the base of their envelope convection zone. The Î´ Sct stars pulsate in low-order g- and p-modes with periods of order 2 hr, driven by the Îº mechanism operating in the He II ionization zone. Theory predicts an overlap region in the Hertzsprung-Russell diagram between instability regions, where "hybrid" stars pulsating in both types of modes should exist. The two types of modes with properties governed by different portions of the stellar interior provide complementary model constraints. Among the known Î³ Dor and Î´ Sct stars, only four have been confirmed as hybrids. Now, analysis of combined Quarter 0 and Quarter 1 Kepler data for hundreds of variable stars shows that the frequency spectra are so rich that there are practically no pure Î´ Sct or Î³ Dor pulsators, i.e., essentially all of the stars show frequencies in both the Î´ Sct and the Î³ Dor frequency range. A new observational classification scheme is proposed that takes into account the amplitude as well as the frequency and is applied to categorize 234 stars as Î´ Sct, Î³ Dor, Î´ Sct/Î³ Dor or Î³ Dor/Î´ Sct hybrids. [less ▲]Detailed reference viewed: 28 (2 ULg) Kepler observations: Light shed on the hybrid γ Doradus - δ Scuti pulsation phenomenonGrigahcène, A.; Uytterhoeven, K.; Antoci, V. et alin Astronomische Nachrichten (2010), 331Through the observational study of stellar pulsations, the internal structure of stars can be probed and theoretical models can be tested. The main sequence γ Doradus (Dor) and δ Scuti (Sct) stars with ... [more ▼]Through the observational study of stellar pulsations, the internal structure of stars can be probed and theoretical models can be tested. The main sequence γ Doradus (Dor) and δ Scuti (Sct) stars with masses 1.2-2.5 M[SUB]ȯ[/SUB] are particularly interesting for asteroseismic study. The γ Dor stars pulsate in high-order gravity (g) modes, with pulsational periods of order of one day. The δ Sct stars, on the other hand, show low-order g and pressure (p) modes with periods of order of 2 hours. Theory predicts the existence of hybrid' stars, i.e. stars pulsating in both types of modes, in an overlap region between the instability strips of γ Dor and δ Sct stars in the Hertzsprung-Russell diagram. Hybrid stars are particularly interesting as the two types of modes probe different regions of the stellar interior and hence provide complementary model constraints. Before the advent of Kepler, only a few hybrid stars had been confirmed. The {{Kepler}} satellite is providing a true revolution in the study of and search for hybrid stars. Analysis of the first 50 days of {{Kepler}} data of hundreds of γ Dor and δ Sct candidates reveals extremely rich frequency spectra, with most stars showing frequencies in both the δ Sct and γ Dor frequency range. As these results show that there are practically no pure δ Sct or γ Dor pulsators, a new observational classification scheme is proposed by \cite{Grig10}. We present their results and characterize 234 stars in terms of δ Sct, γ Dor, δ Sct/γ Dor or γ Dor/δ Sct hybrids. [less ▲]Detailed reference viewed: 19 (2 ULg) Long term photometric monitoring with the Mercator telescope. Frequencies and mode identification of variable O-B starsDe Cat, P.; Briquet, Maryline ; Aerts, C. et alin Astronomy and Astrophysics (2007), 463Aims. We selected a large sample of O-B stars that were considered as (candidate) slowly pulsating B, beta Cep, and Maia stars after the analysis of their hipparcos data. We analysed our new seven ... [more ▼]Aims. We selected a large sample of O-B stars that were considered as (candidate) slowly pulsating B, beta Cep, and Maia stars after the analysis of their hipparcos data. We analysed our new seven passband geneva data collected for these stars during the first three years of scientific operations of the mercator telescope. We performed a frequency analysis for 28 targets with more than 50 high-quality measurements to improve their variability classification. For the pulsating stars, we tried both to identify the modes and to search for rotationally split modes. Methods: We searched for frequencies in all the geneva passbands and colours by using two independent frequency analysis methods and we applied a 3.6 S/N-level criterion to locate the significant peaks in the periodograms. The modes were identified by applying the method of photometric amplitudes for which we calculated a large, homogeneous grid of equilibrium models to perform a pulsational stability analysis. When both the radius and the projected rotational velocity of an object are known, we determined a lower limit for the rotation frequency to estimate the expected frequency spacings in rotationally split pulsation modes. Results: We detected 61 frequencies, among which 33 are new. We classified 21 objects as pulsating variables (7 new confirmed pulsating stars, including 2 hybrid beta Cep/SPB stars), 6 as non-pulsating variables (binaries or spotted stars), and 1 as photometrically constant. All the Maia candidates were reclassified into other variability classes. We performed mode identification for the pulsating variables for the first time. The most probable l value is 0, 1, 2, and 4 for 1, 31, 9, and 5 modes, respectively, including only 4 unambiguous identifications. For 7 stars we cannot rule out that some of the observed frequencies belong to the same rotationally split mode. For 4 targets we may begin to resolve close frequency multiplets. Based on observations collected with the p7 photometer attached to the Flemish 1.2-m mercator telescope situated at the Roque de los Muchachos observatory on La Palma (Spain). Section [see full textsee full text], including Figs. is only available in electronic form at http://www.aanda.org, and Tables 2 and 3 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/463/243 [less ▲]Detailed reference viewed: 51 (1 ULg) A study of bright southern slowly pulsating B stars. III. Mode identification for singly-periodic targets in spectroscopyDe Cat, P.; Briquet, Maryline ; Daszynska-Daszkiewicz, J. et alin Astronomy and Astrophysics (2005), 432We present the results of the mode identification for a sample of 7 bright southern slowly pulsating B stars showing one pulsation frequency in the lambdalambda 413 nm Si II profiles. We combined the ... [more ▼]We present the results of the mode identification for a sample of 7 bright southern slowly pulsating B stars showing one pulsation frequency in the lambdalambda 413 nm Si II profiles. We combined the results from (1) the method of photometric amplitudes; (2) the moment method; and (3) the amplitude and phase variation across the profile to search for the l and m values of the modes best fitting the data. It is the first time that the applicability of these techniques is tested to a sample of main-sequence g-mode pulsators. Combining the moment method with the amplitude and phase variations across the observed line profile gives an improvement in spectroscopic identification of low degree l g-mode pulsations. Using the variations of the higher order even moments < v[SUP]4[/SUP]> and < v[SUP]6[/SUP]> of the moment method solutions can also help. For HD 181558, HD 24587, HD 140873 and HD 177863, the photometric and spectroscopic results are compatible and point towards (l,m) = (1, +1) sectoral modes. For HD 215573, HD 53921 and HD 92287, the results are inconclusive. Our proposed methodology for mode identification is also applicable to gamma Doradus stars. Based on observations collected with the CAT Telescope of the European Southern Observatory and with the Swiss Photometric Telescope of the Geneva Observatory, both situated at La Silla in Chile. [less ▲]Detailed reference viewed: 10 (1 ULg) Asteroseismology of the β Cephei star ν Eridani - III. Extended frequency analysis and mode identificationDe Ridder, J.; Telting, J. H.; Balona, L. A. et alin Monthly Notices of the Royal Astronomical Society (2004), 351Using the large photometric and spectroscopic data sets of the ν Eridani multisite campaign given in our two recent papers (Aerts et al. and Handler et al.), we present an extended frequency analysis and ... [more ▼]Using the large photometric and spectroscopic data sets of the ν Eridani multisite campaign given in our two recent papers (Aerts et al. and Handler et al.), we present an extended frequency analysis and a photometric mode identification. For the extended frequency analysis, we used an improved radial velocity time series, the second-moment time series and the line profiles themselves. In the radial velocity time series, we can now detect an additional pulsation frequency that was previously only found in photometric time series. We also report several new candidate pulsation frequencies. For seven frequencies, the photometric mode identification indicates that they belong to a radial mode and six dipole modes, and for three frequencies the degree l could not be unambiguously determined. We also placed ν Eri in the Hertzsprung-Russell diagram by determining T[SUB]eff[/SUB] using Geneva plus Strömgren photometric calibrations, spectral energy distribution fitting, by non-local thermodynamic equilibrium hydrogen, helium and silicon line profile fitting, and by determining log(L/L[SUB]solar[/SUB]) using the Hipparcos parallax and an Hβ calibration. [less ▲]Detailed reference viewed: 9 (1 ULg) g-mode pulsations in slowly pulsating B starsDe Cat, P.; Daszynska-Daszkiewicz, J.; Briquet, Maryline et alin IAU Colloq. 193: Variable Stars in the Local Group (2004, May 01)In this paper, we give an updated overview of the observed characteristics of g-mode pulsations in slowly pulsating B stars. These characteristics are based on the combined results of linear nonadiabatic ... [more ▼]In this paper, we give an updated overview of the observed characteristics of g-mode pulsations in slowly pulsating B stars. These characteristics are based on the combined results of linear nonadiabatic analysis of the oscillations and a photometric and spectroscopic mode identification for a sample of 13 members. For 4 stars, at least one mode is stable in all the considered theoretical models. [less ▲]Detailed reference viewed: 37 (2 ULg) Asteroseismology of the beta Cep star HD 129929. I. Observations, oscillation frequencies and stellar parametersAerts, C.; Waelkens, C.; Daszynska-Daszkiewicz, J. et alin Astronomy and Astrophysics (2004), 415We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V beta Cep star HD 129929. The dataset has a time base of 21.2 years. The occurrence of a ... [more ▼]We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V beta Cep star HD 129929. The dataset has a time base of 21.2 years. The occurrence of a beating phenomenon is evident from the data. We find evidence for the presence of at least six frequencies, among which we see components of two frequency multiplets with an average spacing of Ë 0.0121 c d[SUP]-1[/SUP] which points towards very slow rotation. This result is in agreement with new spectroscopic data of the star and also with previously taken UV spectra. We provide the amplitudes of the six frequencies in all seven photometric filters. The metal content of the star is Z=0.018± 0.004. All these observational results will be used to perform detailed seismic modelling of this massive star in a subsequent paper. Based on data gathered with the Swiss 0.7m telescope equipped with the photometer P7 of the Geneva Observatory and with the FEROS spectrograph attached to the ESO 2.2 m telescope, both situated at La Silla in Chile; the reduced photometric multicolour data are provided in Table 1, which is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/415/241 [less ▲]Detailed reference viewed: 28 (8 ULg) Asteroseismology of the beta Cep star HD 129929. II. Seismic constraints on core overshooting, internal rotation and stellar parametersDupret, Marc-Antoine ; Thoul, Anne ; Scuflaire, Richard et alin Astronomy and Astrophysics (2004), 415We perform a detailed seismic study of the beta Cep star HD 129929. Our analysis is based on the recent derivation of six pulsation frequencies. These frequencies are unambiguously identified from the ... [more ▼]We perform a detailed seismic study of the beta Cep star HD 129929. Our analysis is based on the recent derivation of six pulsation frequencies. These frequencies are unambiguously identified from the seismic modelling and the photometric amplitudes to be the radial fundamental, the l=1, p[SUB]1[/SUB] triplet, two consecutive components of the l=2, g[SUB]1[/SUB] quintuplet. A non-adiabatic analysis allows us to constrain the metallicity of the star to Z \in [0.016, 0.022]. In addition, the fitting of three independent frequencies, two of which correspond to axisymmetric (m=0) modes, allows us to constrain the core overshooting parameter to alpha[SUB]ov[/SUB]=0.10 ± 0.05, as well as the other global parameters of the star. Finally, from the observation of the l=1 triplet and part of the l=2 quintuplet, we derive constraints on the internal rotation of this star. [less ▲]Detailed reference viewed: 29 (8 ULg) Geneva photometry of HD 129929 (Aerts+, 2004)Aerts, C.; Waelkens, C.; Daszynska-Daszkiewicz, J. et alin SIMBAD (2003), 341We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V {beta} Cep star Hd 129929. The dataset has a time base of 21.2 years. The occurrence of a ... [more ▼]We have gathered and analysed a timeseries of 1493 high-quality multicolour Geneva photometric data of the B3V {beta} Cep star Hd 129929. The dataset has a time base of 21.2 years. The occurrence of a beating phenomenon is evident from the data. We find evidence for the presence of at least six frequencies, among which we see components of two frequency multiplets with an average spacing of ~0.0121c/d which points towards very slow rotation. This result is in agreement with new spectroscopic data of the star and also with previously taken UV spectra. We provide the amplitudes of the six frequencies in all seven photometric filters. The metal content of the star is Z=0.018+/-0.004. All these observational results will be used to perform detailed seismic modelling of this massive star in a subsequent paper. (1 data file). [less ▲]Detailed reference viewed: 19 (4 ULg) A Hare and Hound in a BAG: Asteroseismology of Beta Cephei starsThoul, Anne ; Ausseloos, M.; Barban, C. et alin Communications in Asteroseismology (2003), 143Several members of the COROT Seismology Working Group (SWG) have performed several hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises ... [more ▼]Several members of the COROT Seismology Working Group (SWG) have performed several hare-and-hound'' exercises to prepare the data exploitation of the mission in the past few years. These exercises consist in reproducing a theoretical model on the basis of a light curve obtained from a frequency spectrum computed from an `unknown'' theoretical model of a solar-like or a Delta Scuti star. Members of the BAG (Belgian Asteroseismology Group) have now shown that such an exercise in the mass range of Beta Cephei stars is extremely convincing, making these stars excellent targets for asteroseismology space missions. [less ▲]Detailed reference viewed: 31 (9 ULg) 1