J/A+A/341/553ivo://CDS.VizieR/J/A+A/341/553doi:10.26093/cds/vizier.33410553CDSPetrov P.P.Zajtseva G.V.Efimov Yu.S.Duemmler R.Ilyin I.V.,Tuominen I.Shcherbakov V.A.1999-01-24T15:06:03Z1999-01-24T16:05:57ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsinfrared-photometryvisible-astronomybroad-band-photometrypolarimetryThe T Tauri star RY Tau has increased its brightness from V=10.6mag to V=9.6mag in October-November 1996. By February-March 1997, the star has faded again to V=10.8mag. High-resolution echelle spectra of RY Tau were obtained wit h the SOFIN spectrograph at the Nordic Optical Telescope (La Palma, Spain) at lo w and high brightness levels of the star. No significant changes in the photosph eric lines, which are sensitive to temperature and gravity, were noticed. The spectral type of RY Tau is defined as G1-2IV, which in combination with photomet ric data implies A_V_=1.0-1.3mag. Polarimetric patrol of RY Tau during the fadin g of the star showed an increase of its intrinsic polarization from 0.5-1.0% at high brightness to about 2% at low brightness in the V, R and I bands. The flux radiated in H{alpha} and the IR Ca II emission lines remained about the same, in spite of the one magnitude difference in the continuum flux. These results indicate that variable obscuration of the star by circumstellar dust clo uds was responsible for the brightness change of RY Tau, and that the emission l ine source is mostly outside of the obscured region.1999A&A...341..553Phttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/341/553CatalogResearchIsServedByTAP VizieR generic servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/341/553https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/341/553http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/341/553https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/341/553https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/341/553http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/341/553GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/A+A/341/553/table2UBV-photometry of RY Tau in 1965-1997recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Datedtime.epochdoubleVmagV magnitudemagphot.mag;em.opt.VfloatB-V? B-V colour indexmagphot.color;em.opt.B;em.opt.VfloatnullableU-B? U-B colour indexmagphot.color;em.opt.U;em.opt.BfloatnullableJ/A+A/341/553/table3Observed and intrinsic polarization of RY Tau in UBVRIJDJulian Datedtime.epochdoubleband[UBVRI] photometric band (U,B,V,R,I)instr.bandpasscharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintmagBrightness in that bandmagphot.magfloatP(obs)Observed polarization in that band%phys.polarizationfloate_P(obs)Mean error of the observed polarization%stat.errorfloatPA(obs)Observed position angle of polarization in that banddegpos.posAng;phys.polarizationfloate_PA(obs)Mean error of observed position angledegstat.errorfloatP(intr)Intrinsic polarization in that band (after correction for interstellar polarization) (1)%phys.polarizationfloate_P(intr)Mean error of intrinsic polarization%stat.errorfloatPA(intr)Position angle of intrinsic polarization in that band (after correction for interstellar polarization)degpos.posAng;phys.polarizationfloate_PA(intr)Mean error of position angle of intrinsic polarizationdegstat.errorfloat