Search results for " cosmogonia"

showing 3 items of 83 documents

8.4GHz VLBI observations of SN2004et in NGC6946

2007

We report on 8.4GHz Very Long Baseline Interferometry (VLBI) observations of the type II-P supernova SN2004et in the spiral galaxy NGC 6946, made on 20 February 2005 (151 days after explosion). The Very Large Array (VLA) flux density was 1.23$\pm$0.07 mJy, corresponding to an isotropic luminosity at 8.4GHz of (4.45$\pm$0.3)$\times10^{25}$ erg s$^{-1}$ Hz$^{-1}$ and a brightness temperature of (1.3$\pm$0.3)$\times10^{8}$ K. We also provide an improved source position, accurate to about 0.5 mas in each coordinate. The VLBI image shows a clear asymmetry. From model fitting of the size of the radio emission, we estimate a minimum expansion velocity of 15,700$\pm$2,000 km s$^{-1}$. This velocity…

media_common.quotation_subjectFOS: Physical sciencesIndividualAstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICAAstrophysicsAsymmetryLuminositylaw.inventionlawVery-long-baseline interferometryNGC 6946media_commonPhysicsSpiral galaxyImage (category theory)Astrophysics (astro-ph)Astronomy and AstrophysicsGalaxiesStars:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]SynchrotronSupernovaRadio continuumSupernovaeSpace and Planetary ScienceBrightness temperatureGalaxies ; Individual ; NGC 6946 ; Radio continuum ; Stars ; Supernovae ; SN 2004etUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogoniaSN 2004et:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]
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Pulsating B and Be stars in the Small Magellanic Cloud

2008

Context: Stellar pulsations in main-sequence B-type stars are driven by the kappa-mechanism due to the Fe-group opacity bump. The current models do not predict the presence of instability strips in the B spectral domain at very low metallicities. As the metallicity of the SMC is lower than Z=0.005, it constitutes a very suitable object to test these predictions. Aims: The main objective is to investigate the existence of B-type pulsators at low metallicities, searching for short-term periodic variability in absorption-line B and Be stars in the SMC. The analysis has been performed in a sample of 313 B and Be stars with fundamental astrophysical parameters accurately determined from high-res…

oscillations [stars]statistics [Stars]Be starHertzsprung–Russell diagramMetallicityFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics01 natural sciencesStars : emission-line Be; stars : oscillations; Stars : early-type; Stars : statistics; Galaxies : Magellanic Cloudssymbols.namesakeMagellanic Clouds [Galaxies]early-type [Stars]0103 physical sciencesAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::GalaxiasAstrophysics::Galaxy AstrophysicsPhysics010308 nuclear & particles physicsAstrophysics (astro-ph)Astronomy and AstrophysicsLight curveGalaxy:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Galaxias [UNESCO]Stars13. Climate actionSpace and Planetary Scienceemission-line Be [Stars]symbolsSmall Magellanic CloudAstrophysics::Earth and Planetary AstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::EstrellasInstability strip:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Estrellas [UNESCO]
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A photometric study of Be stars located in the seismology fields of COROT

2007

Context: In preparation for the COROT mission, an exhaustive photometric study of Be stars located in the seismology fields of the COROT mission has been performed. The very precise and long-time-spanned photometric observations gathered by the COROT satellite will give important clues of the origin of the Be phenomenon. Aims: The aim of this work is to find short-period variable Be stars located in the seismology fields of COROT and to study and characterise their pulsational properties. Methods: Light curves obtained at the Observatorio de Sierra Nevada together with data from Hipparcos and ASAS-3 of a total of 84 Be stars have been analysed in order to search for short-term variations. W…

statistics [Stars]:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Otras [UNESCO]FOS: Physical sciencesoscillations (including pulsations) [Stars]Context (language use)AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics01 natural sciences0103 physical sciencesUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::OtrasAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsAstrophysics::Galaxy AstrophysicsPhysics010308 nuclear & particles physicsphotometric [Techniques]Astrophysics (astro-ph)Astronomy and AstrophysicsLight curveStars : emission-line Be; Stars : oscillations (including pulsations); Stars : statistics; Techniques : photometricStarsemission-line Be [Stars]Space and Planetary ScienceSatelliteAstrophysics::Earth and Planetary AstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::EstrellasSeismology:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia::Estrellas [UNESCO]
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