J/MNRAS/455/357ivo://CDS.VizieR/J/MNRAS/455/357doi:10.26093/cds/vizier.74550357CDSSahlmann J.Lazorenko P.F.Bouy H.Martin E.L.Queloz D.Segransan D.,Zapatero Osorio M.R.2024-08-15T20:16:58Z2017-08-28T13:16:02ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frstandard-starsastrometryproper-motionsvisible-astronomytrigonometric-parallaxWe used the OSIRIS camera at the 10.4m Gran Telescopio Canarias (GTC) to monitor the astrometric motion of the L4.5 dwarf 2M1821+14 over 17 months. The astrometric residuals of 11 epochs have an rms dispersion of 0.4mas, which is larger than the average precision of 0.23mas per epoch and hints towards an additional signal or excess noise. Comparison of the point-spread functions in OSIRIS and FORS2/VLT images reveals no differences critical for high-precision astrometry, despite the GTC's segmented primary mirror. We attribute the excess noise to an unknown effect that may be uncovered with additional data. For 2M1821+14, we measured a relative parallax of 10^6.15^+/-0.18mas and determined a correction of 0.50+/-0.05mas to absolute parallax, leading to a distance of 9.38+/-0.03pc. We excluded at 3{sigma} confidence the presence of a companion to 2M1821+14 down to a mass ratio of 0.1 (~5M_Jupiter_) with a period of 50-1000d and a separation of 0.1-0.7au. The accurate parallax allowed us to estimate the age and mass of 2M1821+14 of 120-700Myr and 0.049^+0.014^_-0.024_M_{sun}_, thus confirming its intermediate age and substellar mass. We complement our study with a parallax and proper motion catalogue of 587 stars (i'=~15.5-22) close to 2M1821+14, used as astrometric references. This study demonstrates submas astrometry with the GTC, a capability applicable for a variety of science cases including the search for extrasolar planets and relevant for future astrometric observations with E-ELT and TMT.2016MNRAS.455..357Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/455/357CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/455/357https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/455/357http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/455/357https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/455/357https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/455/357http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/455/357GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/455/357/table5 (Astrometric catalogue)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/455/357/table5?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/455/357/table5?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/455/357/table5?GETtext/xml+votable180.050000true275.363485914.20139810.0055555555555555566/31871 31957https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/455/357?format=asciiOpticaldefaultJ/MNRAS/455/357/table5Astrometric cataloguerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNStar sequential numbermeta.recordinti'magi' magnitudemagphot.mag;em.opt.Ifloate_i'magrms uncertainty on i'magmagstat.error;phot.mag;em.opt.IfloatRAJ2000Right ascension (J2000)degpos.eq.ra;meta.maine_RAJ2000rms uncertainty on RAdegarcsecstat.error;pos.eq.rafloatDEJ2000Declination (J2000)degpos.eq.dec;meta.maine_DEJ2000rms uncertainty on DEdegarcsecstat.error;pos.eq.decfloatpmRARelative proper motion along RA, pmRA*cosDEmas/yrpos.pm;pos.eq.rafloate_pmRArms uncertainty on pmRAmas/yrstat.error;pos.pm;pos.eq.rafloatpmDERelative proper motion along DEmas/yrpos.pm;pos.eq.decfloate_pmDErms uncertainty on pmDEmas/yrstat.error;pos.pm;pos.eq.decfloatrhoAngular distance (differential chromatic refraction (DCR) parameter {rho})maspos.angDistancefloate_rhorms uncertainty on rhomasstat.errorfloatvarpiRelative parallaxmaspos.parallaxfloate_varpirms uncertainty on varpimasstat.errorfloatEp-2000Mean epoch of observation (Ep-2000)yrtime.epochfloatQualchi^2^ value for the epoch residuals that flags the quality of the fitstat.fit.chi2float