Search results for " brown dwarfs"

showing 3 items of 3 documents

The brown dwarf population in the Chamaeleon I cloud

2003

We present the results of a multiband survey for brown dwarfs in the Chamaeleon I dark cloud with the Wide Field Imager (WFI) camera at the ESO/MPG 2.2-m telescope on La Silla (Chile). The survey has revealed a substantial population of brown dwarfs in this southern star forming region. Candidates were selected from R, I and H-alpha imaging observations. We also observed in two medium-band filters, M855 and M915, for the purpose of spectral type determination. The former filter covers a wavelength range containing spectral features characteristic of M-dwarfs, while the latter lies in a relatively featureless wavelength region for these late-type objects. A correlation was found between spec…

InfraredPopulationBrown dwarfFOS: Physical sciencesAstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICAAstrophysicsStellar classificationPhotometry (optics)Stars formationAstrophysics::Solar and Stellar AstrophysicseducationAstrophysics::Galaxy AstrophysicsPhysicseducation.field_of_studyBrown dwarfsStar formationAstrophysics (astro-ph)Luminosity functionAstronomy and AstrophysicsLow-massCircumstellar matterStars:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]Pre-main sequenceLow-mass ; Brown dwarfs ; Stars ; Pre-main sequence ; Stars formation ; Luminosity function ; Mass function ; Circumstellar matterStarsSpace and Planetary ScienceMass functionChamaeleonAstrophysics::Earth and Planetary AstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]
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An X-shooter survey of star forming regions: Low-mass stars and sub-stellar objects

2011

We present preliminary results of our X-shooter survey in star forming regions. In this contribution we focus on sub-samples of young stellar and sub-stellar objects (YSOs) in the Lupus star forming region and in the TW Hya association. We show that the X-shooter spectra are suitable for conducting several parallel studies such as YSO + disk fundamental parameters, accretion and outflow activity in the very low-mass (VLM) and sub-stellar regimes, as well as magnetic activity in young VLM YSOs, and Li abundance determinations. The capabilities of X-shooter in terms of wide spectral coverage, resolution and limiting magnitudes, allow us to assess simultaneously the accretion/outflow, magnetic…

PhysicsYoung stellar objectBrown dwarfAstronomyAstronomy and AstrophysicsAstrophysicsAccretion (astrophysics)Spectral lineT Tauri starStarsaccretion accretion disks ISM: jets and outflows stars: formation stars: low-mass brown dwarfs stars: pre-main sequence T Tauri starsSpace and Planetary ScienceOutflowLow Massjets and outflows stars: formation stars: low-mass brown dwarfs stars: pre-main sequence T Tauri stars [accretion accretion disks ISM]
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The enigmatic young brown dwarf binary FU Tau: accretion and activity

2010

FU Tau belongs to a rare class of young, wide brown dwarf binaries. We have resolved the system in a Chandra X-ray observation and detected only the primary, FU Tau A. Hard X-ray emission, presumably from a corona, is present but, unexpectedly, we detect also a strong and unusually soft component from FU Tau A. Its X-ray properties, so far unique among brown dwarfs, are very similar to those of the T Tauri star TW Hya. The analogy with TW Hya suggests that the dominating soft X-ray component can be explained by emission from accretion shocks. However, the typical free-fall velocities of a brown dwarf are too low for an interpretation of the observed X-ray temperature as post-shock region. O…

accretion accretion discs stars: activity brown dwarfs stars: pre-main-sequence X-rays: starsSettore FIS/05 - Astronomia E AstrofisicaAstrophysics - Solar and Stellar AstrophysicsAstrophysics::High Energy Astrophysical PhenomenaAstrophysics::Solar and Stellar AstrophysicsFOS: Physical sciencesAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysics::Earth and Planetary AstrophysicsAstrophysics::Galaxy AstrophysicsSolar and Stellar Astrophysics (astro-ph.SR)
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