J/MNRAS/486/4590ivo://CDS.VizieR/J/MNRAS/486/4590doi:10.26093/cds/vizier.74864590CDSContreras Pena C.Naylor T.Morrell S.2024-08-19T20:18:27Z2023-01-10T12:54:29ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsvariable-starsyoung-stellar-objectsvisible-astronomyapparent-magnitudeWe have determined the rate of large accretion events in Class I and II young stellar objects (YSOs) by comparing the all-sky digitized photographic plate surveys provided by SuperCOSMOS with the latest data release from Gaia (DR2). The long mean baseline of 55yr along with a large sample of Class II YSOs (~15000) allows us to study approximately 1 million YSO-years. We find 139 objects with {Delta}R>=1mag, most of which are found at amplitudes between 1 and 3mag. The majority of YSOs in this group show irregular variability or long-lasting fading events, which is best explained as hotspots due to accretion or by variable extinction. There is a tail of YSOs at {Delta}R>=3mag and they seem to represent a different population. Surprisingly many objects in this group show high-amplitude irregular variability over time-scales shorter than 10yr, in contrast with the view that high-amplitude objects always have long outbursts. However, we find six objects that are consistent with undergoing large, long-lasting accretion events, three of them previously unknown. This yields an outburst recurrence time-scale of 112kyr, with a 68 per cent confidence interval [74-180]kyr. This represents the first robust determination of the outburst rate in Class II YSOs and shows that YSOs in their planet-forming stage do in fact undergo large accretion events, and with time-scales of ~100000yr. In addition, we find that outbursts in the Class II stage are ~10 times less frequent than during the Class I stage.2019MNRAS.486.4590Chttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/486/4590CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toI/345 : Gaia DR2 (Gaia Collaboration 2018)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/486/4590https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/MNRAS/486/4590http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/MNRAS/486/4590https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/MNRAS/486/4590https://vizier.iucaa.in/viz-bin/votable?-source=J/MNRAS/486/4590http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/MNRAS/486/4590GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/MNRAS/486/4590/table2 (The 139 high-amplitude variable stars detected in our analysis)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/MNRAS/486/4590/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/MNRAS/486/4590/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/MNRAS/486/4590/table2?GETtext/xml+votable180.050000true314.723833344.25786110.0055555555555555566/859 1111 1124 1208 1231 1242 1287 1299 1539 3300-3302 3310 14029 14352 14670 14676 15363 15368 15397 15420 15477-15478 15648 15682-15684 15759 16197 21274 21396 21408 21427 21435-21436 21438 21458 21480 21643 22039 22042 22249 22787 22801 22805 22829 22834 22851 22854 22856 22859 22876 23027 23549 23560 23637 23639 23644 23704 23719 23727 23795 24158 24376 24740 28827 28830 29113 29284 29457 30218 30339 30343 30354 30363 30366 30388 30645 36956-36957 37351 39125 39132 39250 39254 39259 39281 39283 39375 39410 41518 41657-41658 41731 41740 41820 42211 42233 42450 42462 42596 42598 42611 42614 42621 42736 42786 42972 42984 44377https://cdsarc.cds.unistra.fr/viz-bin/moc/J/MNRAS/486/4590?format=asciiOpticaldefaultJ/MNRAS/486/4590/table2The 139 high-amplitude variable stars detected in our analysisSimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDInternal object identifier (VNNN)meta.id;meta.maincharf_ID[*] Flag on ID (1)meta.codecharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainSNameSimbad namemeta.idcharSclassObject type from Simbadsrc.classcharDeltaRObserved R amplitude taking into account only the SSS and Gaia epochs (2)magphot.mag;arith.difffloatLCClassClassification for the behaviour of the light curve of the YSOsrc.classcharClassFinal classification of the light curvesrc.classcharr_ClassReferences for Class (3)meta.ref;pos.framecharKnown[YN] Indicates whether the object is a known variable starmeta.codecharSSS[YN] Indicates whether the SSS versus Gaia variability relates to the known variability of the sourcemeta.codecharLCLight curvemeta.ref.urlcharYSOSource used to classify the YSOs as being in the Class II stage (4)meta.bibcharJ/MNRAS/486/4590/table1Photometry for 139 high-amplitude variable starsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDInternal object identifier (VNNN)meta.id;meta.maincharMJDModified Julian date of the observations (JD-2400000.5)dtime.epochdoubleindexedrmagR- or r-band magnitudemagphot.mag;em.opt.RfloatFilter[rR] Filter used to obtain the magnitudeinstr.setup;instr.filtercharSurveySurvey from which the magnitude was extractedmeta.notecharn_rmagNote on rmag (1)meta.notechar