J/A+A/557/A77ivo://CDS.VizieR/J/A+A/557/A77doi:10.26093/cds/vizier.35570077CDSBouvier J.Grankin K.Ellerbroek L.Bouy H.Barrado D.2017-06-13T11:08:30Z2013-09-04T06:37:59ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsvariable-starsphotometryAA Tau has been monitored for more than 20 years since 1987, exhibiting a nearly constant brightness level of V=12.5mag. We report here that in 2011 it suddenly faded away, becoming 2 magnitudes fainter in the V-band, and has remained in this deep state since then. We investigate the origin of the sudden dimming of the AA Tau system. We report new optical and near-IR photometry and spectroscopy obtained during the fading event.2013A&A...557A..77Bhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/557/A77CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/A+A/349/619 : UBVRI light curves of AA Tau in 1995 (Bouvier+, 1999)J/A+A/409/169 : UBVRI light curves of AA Tau in 1999 (Bouvier+, 2003)J/A+A/463/1017 : B and V light curves of AA Tau (Bouvier+, 2007)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/557/A77https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/557/A77http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/557/A77https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/557/A77https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/557/A77http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/557/A77GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tap3.322582951404819e-19 3.852589004194616e-19OpticaldefaultJ/A+A/557/A77/aatauAA Tau photometric measurements obtained at Crimean Astrophysical Observatory from 2007 to 2013recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintHJDHeliocentric Julian datedtime.epochdoubleVmagJohnson V magnitudemagphot.mag;em.opt.VfloatV-R? Johnson (V-R) color indexmagphot.color;em.opt.V;em.opt.RfloatnullableObsObservation at Maidanak or CrAO (maid or crao)meta.id;instr.obstychar