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 References of "Montalban Iglesias, Josefa"      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 61 to 80 of 92     1 2 3 4 5     Discriminating between overshooting and rotational mixing in massive stars: any help from asteroseismology?Miglio, Andrea ; Montalban Iglesias, Josefa ; Eggenberger, P. et alin Communications in Asteroseismology (2009, July 01), 158Chemical turbulent mixing induced by rotation can affect the internal distribution of μ near the energy-generating core of main-sequence stars, having an effect on the evolutionary tracks similar to that ... [more ▼]Chemical turbulent mixing induced by rotation can affect the internal distribution of μ near the energy-generating core of main-sequence stars, having an effect on the evolutionary tracks similar to that of overshooting. However, this mixing also leads to a smoother chemical composition profile near the edge of the convective core, which is reflected in the behavior of the buoyancy frequency and, therefore, in the frequencies of gravity modes. We show that for rotational velocities typical of main-sequence B-type pulsating stars, the signature of a rotationally induced mixing significantly perturbs the spectrum of gravity modes and mixed modes, and can be distinguished from that of overshooting. The cases of high-order gravity modes in Slowly Pulsating B stars and of low-order g modes and mixed modes in β Cephei stars are discussed. [less ▲]Detailed reference viewed: 5 (0 ULg) Uncertainties in the chemical composition of B-type stars: effects on the opacity and on the excitation of pulsation modesMontalban Iglesias, Josefa ; Miglio, Andrea ; Morel, Thierry in Communications in Asteroseismology (2009), 158Recent determinations of element abundances in early-B stars have shown a significant discrepancy with those derived for the Sun. Î² Cep pulsators are early-B stars whose pulsations are driven by the ... [more ▼]Recent determinations of element abundances in early-B stars have shown a significant discrepancy with those derived for the Sun. Î² Cep pulsators are early-B stars whose pulsations are driven by the opacity mechanism operating at the Fe-group opacity bump (e.g. Dziembowski & Pamyatnykh 1993). Since each element contributes differently to the stellar opacity in the Z-bump region, differences in the metal mixture may affect the pulsation properties of these early-B stars. Here we study the role of different elements in the stellar opacity of B-type stars, and the consequences of the uncertainties in the composition of the metal mixture for the instability strip of Î²~Cep stars. [less ▲]Detailed reference viewed: 21 (5 ULg) Ledoux's convection criterion in evolution and asteroseismology of massive starsLebreton, Yves; Montalban Iglesias, Josefa ; Godart, Mélanie et alin Communications in Asteroseismology (2009), 158Saio et al. (2006) have shown that the presence of an intermediate convective zone (ICZ) in post-main sequence models could prevent the propagation of g-modes in the radiative interior and hence avoid the ... [more ▼]Saio et al. (2006) have shown that the presence of an intermediate convective zone (ICZ) in post-main sequence models could prevent the propagation of g-modes in the radiative interior and hence avoid the corresponding radiative damping. The development of such a convective region highly depends on the structure of the star in the mu-gradient region surrounding the convective core during the main sequence phase. In particular,the development of this ICZ depends on physical processes such as mass loss, overshooting (Chiosi & Maeder 1986, Chiosi et al. 1992, see also Godart et al., 2009) and convective instability criterion (Schwarzschild's or Ledoux's criteria). In this paper we study the consequences of adopting the Ledoux's criterion on the evolution of the convective regions in massive stars (15 and 20 M_{o}), and on the pulsation spectrum of these new B-type variables (also called SPBsg). [less ▲]Detailed reference viewed: 22 (2 ULg) Testing the forward approach in modelling β Cephei pulsators: setting the stageMiglio, A.; Montalban Iglesias, Josefa ; Thoul, Anne in Communications in Asteroseismology (2009)The information on stellar parameters and on the stellar interior we can get by studying pulsating stars depends crucially on the available observational constraints: both seismic constraints (precision ... [more ▼]The information on stellar parameters and on the stellar interior we can get by studying pulsating stars depends crucially on the available observational constraints: both seismic constraints (precision and number of detected modes, identification, nature of the modes) and classical'' observations (photospheric abundances, effective temperature, luminosity, surface gravity). We consider the case of β Cephei pulsators and, with the aim of estimating quantitatively how the available observational constraints determine the type and precision of our inferences, we set the stage for Hare&Hound exercises. In this contribution we present preliminary results for one simple case, where we assume as observed'' frequencies a subset of frequencies of a model and then evaluate a seismic merit function on a dense and extensive grid of models of B-type stars. We also compare the behaviour of χ^2 surfaces obtained with and without mode identification. [less ▲]Detailed reference viewed: 16 (1 ULg) CoRot B star frequency analysis (Degroote+, 2009)Degroote, P.; Aerts, C.; Ollivier, M. et alComputer development (2009)Results of frequency analyses for 352 candidate B pulsators (candidate Be stars are ommitted) from CoRoT's initial run. For each star, the following information is given: frequency number, amplitude ... [more ▼]Results of frequency analyses for 352 candidate B pulsators (candidate Be stars are ommitted) from CoRoT's initial run. For each star, the following information is given: frequency number, amplitude + error, frequency value + error, phase + error. The error values for large amplitude frequencies can be slightly underestimated, as they are not corrected for correlation effects. Also given are comments about every frequency: if they are expected to be due to instrumental effects (e.g. orbit of the satellite), if they are harmonics or higher order combinations of previously identified frequencies. (2 data files). [less ▲]Detailed reference viewed: 18 (7 ULg) Communications in Asteroseismology, Vol.158, Proceedings of "38th Liege International Astrophysical Colloquium: Evolution and Pulsation of Massive Stars on the Main Sequence and Close to it"Noels-Grötsch, Arlette ; Aerts, conny; Montalban Iglesias, Josefa et alBook published by Austrian Academy of Sciences Press (2009)Detailed reference viewed: 4 (0 ULg) VLT transit and occultation photometry for the bloated planet CoRoT-1bGillon, Michaël ; Demory, B.-O.; Triaud, A.H.M.J. et alin Astronomy and Astrophysics (2009), 506We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new ... [more ▼]We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 microns. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07 (+0.13,-0.18) M_Jup and 1.45 (+0.07,-0.13) R_Jup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09 microns (0.278 (+0.043,-0.066) %) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet. [less ▲]Detailed reference viewed: 90 (14 ULg) First asteroseismic results from CoRoTMichel, Eric; Baglin, A.; Weiss, W. W. et alin Communications in Asteroseismology (2008), 156About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first ... [more ▼]About one year after the end of the first observational run and six months after the first CoRoT data delivery, we comment the data exploitation progress for different types of stars. We consider first results to illustrate how these data of unprecedented quality shed a new light on the field of stellar seismology. [less ▲]Detailed reference viewed: 46 (18 ULg) Preliminary seismic study of the gamma Doradus COROT target HD 49434Bouabid, M.-P.; Uytterhoeven, K.; Miglio, Andrea et alin Communications in Asteroseismology (2008), 157Detailed reference viewed: 18 (7 ULg) Driving and damping mechanisms in hybrid pressure-gravity modes pulsatorsDupret, Marc-Antoine ; Miglio, Andrea ; Montalban Iglesias, Josefa et alin Journal of Physics: Conference Series (2008), 118We study the energetic aspects of hybrid pressure-gravity modes pulsations. The case of hybrid beta Cephei-SPB pulsators is considered with special attention. In addition to the already known sensitivity ... [more ▼]We study the energetic aspects of hybrid pressure-gravity modes pulsations. The case of hybrid beta Cephei-SPB pulsators is considered with special attention. In addition to the already known sensitivity of the driving mechanism to the heavy elements mixture (mainly the iron abundance), we show that the characteristics of the propagation and evanescent regions play also a major role, determining the extension of the stable gap in the frequency domain between the unstable low order pressure and high order gravity modes. Finally, we consider the case of hybrid delta Sct-gamma Dor pulsators. [less ▲]Detailed reference viewed: 16 (5 ULg) A seismic approach to testing different formation channels of subdwarf B starsHu, Haili; Dupret, Marc-Antoine ; Aerts, C. et alin Astronomy and Astrophysics (2008), 490Context: There are many unknowns in the formation of subdwarf B stars. Different formation channels are considered to be possible and to lead to a variety of helium-burning subdwarfs. All seismic models ... [more ▼]Context: There are many unknowns in the formation of subdwarf B stars. Different formation channels are considered to be possible and to lead to a variety of helium-burning subdwarfs. All seismic models to date, however, assume that a subdwarf B star is a post-helium-flash-core surrounded by a thin inert layer of hydrogen. Aims: We examine an alternative formation channel, in which the subdwarf B star originates from a massive (>~2 M[SUB]o[/SUB]) red giant with a non-degenerate helium-core. Although these subdwarfs may evolve through the same region of the log g-T_eff diagram as the canonical post-flash subdwarfs, their interior structure is rather different. We examine how this difference affects their pulsation modes and whether it can be observed. Methods: Using detailed stellar evolution calculations we construct subdwarf B models from both formation channels. The iron accumulation in the driving region due to diffusion, which causes the excitation of the modes, is approximated by a Gaussian function. The pulsation modes and frequencies are calculated with a non-adiabatic pulsation code. Results: A detailed comparison of two subdwarf B models from different channels, but with the same log g and T_eff, shows that their mode excitation is different. The excited frequencies are lower for the post-flash than for the post-non-degenerate subdwarf B star. This is mainly due to the differing chemical composition of the stellar envelope. A more general comparison between two grids of models shows that the excited frequencies of most post-non-degenerate subdwarfs cannot be well-matched with the frequencies of post-flash subdwarfs. In the rare event that an acceptable seismic match is found, additional information, such as mode identification and log g and T_eff determinations, allows us to distinguish between the two formation channels. [less ▲]Detailed reference viewed: 20 (2 ULg) CLÉS, Code Liégeois d'Évolution StellaireScuflaire, Richard ; Théado, Sylvie; Montalban Iglesias, Josefa et alin Astrophysics & Space Science (2008), 316CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want ... [more ▼]CLÉS is an evolution code recently developed to produce stellar models meeting the specific requirements of studies in asteroseismology. It offers the users a lot of choices in the input physics they want in their models and its versatility allows them to tailor the code to their needs and implement easily new features. We describe the features implemented in the current version of the code and the techniques used to solve the equations of stellar structure and evolution. A brief account is given of the use of the program and of a solar calibration realized with it. [less ▲]Detailed reference viewed: 14 (7 ULg) The Liège Oscillation codeScuflaire, Richard ; Montalban Iglesias, Josefa ; Théado, S. et alin Astrophysics & Space Science (2008), 316The Liège Oscillation code can be used as a stand-alone program or as a library of subroutines that the user calls from a Fortran main program of his own to compute radial and nonradial adiabatic ... [more ▼]The Liège Oscillation code can be used as a stand-alone program or as a library of subroutines that the user calls from a Fortran main program of his own to compute radial and nonradial adiabatic oscillations of stellar models. We describe the variables and the equations used by the program and the methods used to solve them. A brief account is given of the use and the output of the program. [less ▲]Detailed reference viewed: 22 (6 ULg) Probing the properties of convective cores through g modes: high-order g modes in SPB and γ Doradus starsMiglio, Andrea ; Montalban Iglesias, Josefa ; Noels-Grötsch, Arlette et alin Monthly Notices of the Royal Astronomical Society (2008), 386(3), 1487-1502In main-sequence stars, the periods of high-order gravity modes are sensitive probes of stellar cores and, in particular, of the chemical composition gradient that develops near the outer edge of the ... [more ▼]In main-sequence stars, the periods of high-order gravity modes are sensitive probes of stellar cores and, in particular, of the chemical composition gradient that develops near the outer edge of the convective core. We present an analytical approximation of high-order g modes that takes into account the effect of the μ gradient near the core. We show that in main-sequence models, similarly to the case of white dwarfs, the periods of high-order gravity modes are accurately described by a uniform period spacing superposed to an oscillatory component. The periodicity and amplitude of such component are related, respectively, to the location and sharpness of the μ gradient. We investigate the properties of high-order gravity modes for stellar models in a mass domain range between 1 and 10M[SUB]solar[/SUB], and the effects of the stellar mass, evolutionary state and extra-mixing processes on period spacing features. In particular, we show that for models of a typical Slowly Pulsating B (SPB) star, a chemical mixing that could likely be induced by the slow rotation observed in these stars is able to significantly change the g-mode spectra of the equilibrium model. Prospects and challenges for the asteroseismology of γ Doradus and SPB stars are also discussed. [less ▲]Detailed reference viewed: 7 (0 ULg) Thorough analysis of input physics in CESAM and CLÉS codesMontalban Iglesias, Josefa ; Lebreton, Yveline; Miglio, Andrea et alin Astrophysics & Space Science (2008), 316(1-4), 219-229This contribution is not about the quality of the agreement between stellar models computed by CESAM and CLÉS codes, but more interesting, on what ESTA-Task 1 run has taught us about these codes and about ... [more ▼]This contribution is not about the quality of the agreement between stellar models computed by CESAM and CLÉS codes, but more interesting, on what ESTA-Task 1 run has taught us about these codes and about the input physics they use. We also quantify the effects of different implementations of the same physics on the seismic properties of the stellar models, that in fact is the main aim of ESTA experiments. [less ▲]Detailed reference viewed: 15 (1 ULg) Gravity modes and mixed modes as probes of stellar cores in main-sequence stars: From solar-like to β Cep starsMiglio, Andrea ; Montalban Iglesias, Josefa ; Eggenberger, P. et alin Astronomische Nachrichten (2008), 329We investigate how the frequencies of gravity modes depend on the detailed properties of the chemical composition gradient that develops near the core of main-sequence stars and, therefore, on the ... [more ▼]We investigate how the frequencies of gravity modes depend on the detailed properties of the chemical composition gradient that develops near the core of main-sequence stars and, therefore, on the transport processes that are able to modify the \mu profile in the central regions. We show that in main-sequence models, similarly to the case of white dwarfs, the periods of high-order gravity modes are accurately described by a uniform period spacing superposed to an oscillatory component. The periodicity and amplitude of such a component are related, respectively, to the location and sharpness of the \mu gradient. We briefly discuss and interpret, by means of this simple approximation, the effect of turbulent mixing near the core on the periods of both high-order and low-order g modes, as well as of modes of mixed pressure-gravity character. [less ▲]Detailed reference viewed: 7 (0 ULg) The effect of turbulent mixing on g-modes spectrum of MS starsMontalban Iglesias, Josefa ; Miglio, Andrea ; Eggenberger, P. et alin Astronomische Nachrichten (2008), 329Understanding transport processes inside stars is one of the main goals of asteroseismology. Chemical turbulent mixing can affect the internal distribution of μ near the energy generating core, having an ... [more ▼]Understanding transport processes inside stars is one of the main goals of asteroseismology. Chemical turbulent mixing can affect the internal distribution of μ near the energy generating core, having an effect on the evolutionary tracks similar to that of overshooting. This mixing leads to a smoother chemical composition profile near the edge of the convective core, which is reflected in the behavior of the buoyancy frequency and, therefore, in the frequencies of gravity modes. We describe the effects of convective overshooting and turbulent mixing on the frequencies of gravity modes in B-type main sequence stars. In particular, the cases of p-g mixed modes in β Cep stars and high-order modes in SPBs are considered. [less ▲]Detailed reference viewed: 9 (0 ULg) Effect of convective outer layers modeling on non-adiabatic seismic observables of delta Scuti starsMontalban Iglesias, Josefa ; Dupret, Marc-Antoine in Astronomy and Astrophysics (2007), 470Context: The identification of pulsation modes in delta Scuti stars is mandatory for constraining the theoretical stellar models. The non-adiabatic observables used in the photometric identification ... [more ▼]Context: The identification of pulsation modes in delta Scuti stars is mandatory for constraining the theoretical stellar models. The non-adiabatic observables used in the photometric identification methods depend, however, on convection modeling in the external layers. Aims: We determine how the treatment of convection in the atmospheric and sub-atmospheric layers affects the mode identification and what information about the thermal structure of the external layers can be obtained from amplitude ratios and phase lags in Strömgren photometric bands. Methods: We derive non-adiabatic parameters for delta Scuti stars by using, for the first time, stellar models with the same treatment of convection in the interior and in the atmosphere. We compute classical non-gray mixing length models, and as well non-gray full spectrum of turbulence'' (FST) models. Furthermore, we compute the photometric amplitudes and phases of pulsation by using the colors and the limb-darkening coefficients as derived from the same atmosphere models as used in the stellar modeling. Results: We show that the non-adiabatic phase-lag is mainly sensitive to the thermal gradients in the external layers, hence to the treatment of convection, and that this sensitivity is also clearly reflected in the multi-color photometric phase differences. [less ▲]Detailed reference viewed: 16 (2 ULg) Revised instability domains of SPB and beta Cephei starsMiglio, Andrea ; Montalban Iglesias, Josefa ; Dupret, Marc-Antoine in Communications in Asteroseismology (2007), 151The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars is known to be very sensitive to opacity changes in the stellar interior where T Ë 2 × 10[SUP]5[/SUP] K. In this region ... [more ▼]The excitation of pulsation modes in beta Cephei and Slowly Pulsating B stars is known to be very sensitive to opacity changes in the stellar interior where T Ë 2 × 10[SUP]5[/SUP] K. In this region differences in opacity up to Ë 50% can be induced by the choice between OPAL and OP opacity tables, and between two different metal mixtures (Grevesse & Noels 1993 and Asplund et al. 2005). We have extended the non-adiabatic computations presented in Miglio et al. (2007) towards models of higher mass and pulsation modes of degree l = 3, and we present here the instability domains in the HR- and log P-log Teff diagrams resulting from different choices of opacity tables, and for three different metallicities. [less ▲]Detailed reference viewed: 8 (2 ULg) Instability strips of main sequence B stars: a parametric study of iron enhancementMiglio, Andrea ; Bourge, P.-O.; Montalban Iglesias, Josefa et alin Communications in Asteroseismology (2007), 150The discovery of beta Cephei stars in low metallicity environments, as well as the difficulty to theoretically explain the excitation of the pulsation modes observed in some beta Cephei and SPB stars ... [more ▼]The discovery of beta Cephei stars in low metallicity environments, as well as the difficulty to theoretically explain the excitation of the pulsation modes observed in some beta Cephei and SPB stars, suggest that the iron opacity bump'' provided by standard models could be underestimated. We investigate, by means of a parametric study, the effect of a local iron enhancement on the location of the beta Cephei and SPB instability strips. [less ▲]Detailed reference viewed: 14 (1 ULg)     1 2 3 4 5