J/A+A/479/827ivo://CDS.VizieR/J/A+A/479/827doi:10.26093/cds/vizier.34790827CDSGrankin K.N.Bouvier J.Herbst W.Melnikov S.Yu.2017-10-12T13:00:41Z2008-04-13T15:47:08ZCDS 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-photometryT Tauri stars exhibit variability on all timescales, whose origin is still debated. On WTTS the variability is fairly simple and attributed to long-lived, ubiquitous cool spots. We investigate the long term variability of WTTS, extending up to 20 years in some cases, characterize it statistically and discuss its implications for our understanding of these stars. We have obtained a unique, homogeneous database of photometric measurements for WTTS extending up to 20-years. It contains more than 9000 UBVR observations of 48 WTTS. All the data were collected at Mount Maidanak Observatory (Uzbekistan) and they constitute the longest homogeneous record of accurate WTTS photometry ever assembled. Definitive rotation periods for 35 of the 48 stars are obtained. Phased light curves over 5 to 20 seasons are now available for analysis. Light curve shapes, amplitudes and colour variations are obtained for this sample and various behaviors exhibited, discussed and interpreted. Our main conclusion is that most WTTS have very stable long term variability with relatively small changes of amplitude or mean light level. The long term variability seen reflects modulation in the cold spot distributions. Photometric periods are stable over many years, and the phase of minimum light can be stable as well for several years. On the long term, spot properties do change in subtle ways, leading to secular variations in the shape and amplitudes of the light curves.2008A&A...479..827Ghttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/479/827CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/479/827https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/479/827http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/479/827https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/479/827https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/479/827http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/479/827GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/479/827/stars (List of the stars)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/479/827/stars?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/479/827/stars?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/479/827/stars?GETtext/xml+votable180.050000true63.36333328.2736110.0055555555555555566/336 350 473 478 489 1030 1040 1050-1052 1114 1140 1154 1159 1165 1168-1170 1199 23533 23542 23549-23551 24222 24300 30741 42981 44378-44379 47742 47828https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/479/827?format=asciiOpticalInfrareddefaultJ/A+A/479/827/starsList of the starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSimbad namemeta.id;meta.maincharRAJ2000Simbad Hour of Right Ascension (J2000.0)pos.eq.ra;meta.mainDEJ2000Simbad Degree of Declination (J2000.0)pos.eq.dec;meta.mainBmag? Simbad B band magnitudemagphot.mag;em.opt.BfloatnullableVmag? Simbad V band magnitudemagphot.mag;em.opt.VfloatnullableSpTypeSimbad MK spectral typesrc.spTypecharPer? Known period (from table3 of paper)dtime.perioddoublenullableFileNameData file name, in "phot" subdirectorymeta.id;meta.filecharSimbadNameSimbad column added by the CDSmeta.idchar