0000000000656937

AUTHOR

Silvia H. P. Alencar

showing 3 related works from this author

The magnetosphere of the close accreting PMS binary V4046 Sgr

2013

V4046 Sagittarii AB is a close short-period classical T Tauri binary. It is a circularised and synchronised system accreting from a circumbinary disk. In 2009 it was observed as part of a coordinated program involving near-simultaneous spectropolarimetric observations with ESPaDOnS at the Canada-France-Hawai'i Telescope and high-resolution X-ray observations with XMM-Newton. Magnetic maps of each star were derived from Zeeman-Doppler imaging. After briefly highlighting the most significant observational findings, we present a preliminary 3D model of the binary magnetosphere constructed from the magnetic maps using a newly developed binary magnetic field extrapolation code. The large-scale f…

accretion young starsQC1-999Astrophysics::High Energy Astrophysical PhenomenaMagnetosphereBinary numberFOS: Physical sciencesAstrophysics01 natural scienceslaw.inventionTelescopeSettore FIS/05 - Astronomia E Astrofisicalaw0103 physical sciencesAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsQCAstrophysics::Galaxy AstrophysicsSolar and Stellar Astrophysics (astro-ph.SR)Physics010308 nuclear & particles physicsPhysicsMagnetic fieldDipoleStarsT Tauri starQC PhysicsAstrophysics - Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsCircumbinary planet
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UV variability and accretion dynamics in the young open cluster NGC 2264

2015

We explore UV and optical variability signatures for several hundred members of NGC 2264 (3 Myr). We performed simultaneous u- and r-band monitoring over two full weeks with CFHT/MegaCam. About 750 young stars are probed; 40% of them are accreting. Statistically distinct variability properties are observed for accreting and non-accreting cluster members. The accretors exhibit a significantly higher level of variability than the non-accretors, especially in the UV. The amount of u-band variability correlates statistically with UV excess in disk-bearing objects, which suggests that accretion and star-disk interaction are the main sources of variability. Cool magnetic spots, several hundred de…

AccretionAstrophysics::High Energy Astrophysical PhenomenaFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsSettore FIS/05 - Astronomia E AstrofisicaStars: low-maAstrophysics::Solar and Stellar Astrophysicsaccretion diskAstrophysics::Galaxy AstrophysicsSolar and Stellar Astrophysics (astro-ph.SR)Stars: variables: T TauriPhysicsPhotosphereHerbig Ae/BeAstronomy and AstrophysicsAstronomy and AstrophysicUltraviolet: starAccretion (astrophysics)StarsWavelengthAmplitudeAstrophysics - Solar and Stellar AstrophysicsSpace and Planetary ScienceOpen clusters and associations: individual: NGC 2264Stars: pre-main sequenceAstrophysics::Earth and Planetary AstrophysicsOpen cluster
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Mapping accretion and its variability in the young open cluster NGC 2264: A study based on u-band photometry

2014

We aim at characterizing the accretion properties of several hundred members of the star-forming cluster NGC 2264 (3 Myr). We performed a deep u,g,r,i mapping and a simultaneous u+r monitoring of the region with CFHT/MegaCam in order to directly probe the accretion process from UV excess measurements. Photometric properties and stellar parameters are determined homogeneously for about 750 monitored young objects, spanning the mass range 0.1-2 Mo. About 40% are classical (accreting) T Tauri stars, based on various diagnostics (H_alpha, UV and IR excesses). The remaining non-accreting members define the (photospheric+chromospheric) reference UV emission level over which flux excess is detecte…

Stellar massAstrophysics::High Energy Astrophysical PhenomenaStars: formationPopulationFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsPhotometry (optics)Accretion rateAccretion accretion diskStars: low-maAstrophysics::Solar and Stellar AstrophysicseducationAstrophysics::Galaxy AstrophysicsSolar and Stellar Astrophysics (astro-ph.SR)Physicseducation.field_of_studyDetection thresholdAstronomy and AstrophysicsAstronomy and AstrophysicUltraviolet: starAccretion (astrophysics)T Tauri starAstrophysics - Solar and Stellar Astrophysicsindividual: NGC 2264; Stars: formation; Stars: low-mass; Stars: pre-main sequence; Ultraviolet: stars; Astronomy and Astrophysics; Space and Planetary Science [Accretion accretion disks; Open clusters and associations]Space and Planetary ScienceOpen clusters and associations: individual: NGC 2264Stars: pre-main sequenceAstrophysics::Earth and Planetary AstrophysicsOpen cluster
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