0000000000465573

AUTHOR

Jean-francois Lestrade

showing 2 related works from this author

Astrometric detection of a low-mass companion orbiting the star AB Doradus

1997

International audience; We report submilliarcsecond-precise astrometric measurements for the late-type star AB Doradus via a combination of VLBI (very long baseline interferometry) and HIPPARCOS data. Our astrometric analysis results in the precise determination of the kinematics of this star, which reveals an orbital motion readily explained as caused by gravitational interaction with a low-mass companion. From the portion of the reÑex orbit covered by our data and using a revised mass of the primary star (0.76 M _) derived from our new value of the parallax (66.3 mas \ n \ 67.2 mas), we Ðnd the dynamical mass of the newly discovered companion to be between 0.08 and 0.11 If accurate photom…

010504 meteorology & atmospheric sciencesGalactic astronomyStellar massBrown dwarfAstrophysicsAstrophysics::Cosmology and Extragalactic Astrophysics01 natural sciencesstars: low-mass0103 physical sciencesVery-long-baseline interferometryAstrophysics::Solar and Stellar Astrophysics010303 astronomy & astrophysicsAstrophysics::Galaxy Astrophysics0105 earth and related environmental sciencesPhysicsstars: individual (AB Doradus)[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR]Astrophysics::Instrumentation and Methods for AstrophysicsAstronomyAstronomy and AstrophysicsAstrometryInterferometrySpace and Planetary Sciencetechniques: interferometricOrbital motionastrometryAstrophysics::Earth and Planetary Astrophysics[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA]stars: kinematicsLow Massbrown dwarfs
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Space-VLBI phase-reference mapping and astrometry

2001

We present 5 GHz space-VLBI observations of the quasar pair B1342+662/B1342+663 that demonstrate the feasibility of phase-reference techniques using an antenna in space. The space-based data were taken by the satellite HALCA, of the space-VLBI mission VSOP. From residual (referenced) phases we derive an upper bound of 10 meters to the uncertainty of the spacecraft orbit reconstruction. An analysis of the phase-reference maps of the sources additionally suggests that the above mentioned uncertaintyis likely not larger than 3 meters. With errors of this magnitude, HALCA is a useful tool for astrometric studies of close pairs of radio sources.

B1342+662B1342+663InterferometricFOS: Physical sciencesAstrophysicsUNESCO::ASTRONOMÍA Y ASTROFÍSICAAstrophysicsVery-long-baseline interferometryQuasarsPhysicsSpacecraftbusiness.industryAstrophysics (astro-ph)Astrophysics::Instrumentation and Methods for AstrophysicsAstronomy and AstrophysicsQuasarAstrometryAstrometryGeodesy:ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogonia [UNESCO]Astrometry ; Interferometric ; Quasars ; B1342+662 ; B1342+663Space and Planetary ScienceMagnitude (astronomy)Orbit (dynamics)SatelliteAntenna (radio)UNESCO::ASTRONOMÍA Y ASTROFÍSICA::Cosmología y cosmogoniabusiness:ASTRONOMÍA Y ASTROFÍSICA [UNESCO]
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