J/ApJ/957/113ivo://CDS.VizieR/J/ApJ/957/113doi:10.26093/cds/vizier/ba-xx-3hCDSWang M.-T.Herczeg G.J.Liu H.-G.Fang M.Johnstone D.Lee H.-G.,Walter F.M.Hambsch F.-J.Contreras Pena C.Lee J.-E.Millward M.,Pearce A.Monard B.Zhou L.2026-07-02T12:00:56Z2026-02-04T16:10:49ZCDS support team

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

cds-question@unistra.frvariable-starsinfrared-photometryvisible-astronomybroad-band-photometryyoung-stellar-objectsEX Lup is the archetype for the class of young stars that undergoes repeated accretion outbursts of ~5mag at optical wavelengths that last for months. Despite extensive monitoring that dates back 130yr, the accretion history of EX Lup remains mostly qualitative and has large uncertainties. We assess historical accretion rates of EX Lup by applying correlations between optical brightness and accretion, developed on multi-band magnitude photometry of the ~2mag optical burst in 2022. Two distinct classes of bursts occur: major outbursts ({Delta}V~5mag) have year-long durations, are rare, reach accretion rates of dM/dt_acc_~10^-7^M_{sun}_/yr at peak, and have a total accreted mass of around 0.1 Earth mass. The characteristic bursts ({Delta}V~2mag) have durations of ~2-3 months, are more common, reach accretion rates of dM/dt_acc_~10^-8^M_{sun}_/yr at peak, and have a total accreted mass of around 10-3 Earth masses. The distribution of total accreted mass in the full set of bursts is poorly described by a power law, which suggests different driving causes behind the major outburst and characteristic bursts. The total mass accreted during two classes of bursts is around 2 times the masses accreted during quiescence. Our analysis of the light curves reveals a color-dependent time lag in the 2022 post-burst light curve, attributed to the presence of both hot and cool spots on the stellar surface.2023ApJ...957..113Whttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/957/113CatalogResearchIsServedByTAP VizieR generic servicerelated-toB/vsx : AAVSO International Variable Star Index VSX (Watson+, 2006-)II/179 : Southern Spectrophotometric Standards. I + II (Hamuy+ 1992,94)I/322 : UCAC4 Catalogue (Zacharias+, 2012)II/328 : AllWISE Data Release (Cutri+ 2013)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)IV/39 : TESS Input Catalog version 8.2 (TIC v8.2) (Paegert+, 2021)I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)J/A+A/507/881 : Emission lines in EX Lup optical spectrum (Sipos+, 2009)J/ApJ/743/156 : NEOWISE obs. of NEOs: preliminary results (Mainzer+, 2011)J/A+A/551/A107 : X-shooter spectra of 24 young stellar objects (Manara+, 2013)J/ApJS/208/9 : Intrinsic colors and temperatures of PMS stars (Pecaut+, 2013)J/A+A/561/A2 : 36 accreting YSOs emission lines (Alcala+, 2014)J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)J/A+A/570/A82 : Mapping accretion variability in NGC 2264 (Venuti+, 2014)J/AJ/150/175 : YSOVAR: infrared photometry in NGC 1333 (Rebull+, 2015)J/A+A/600/A20 : Lupus YSOs X-shooter spectroscopy (Alcala+, 2017)J/MNRAS/465/3011 : VVV high amplitude NIR var. stars (Contreras Pena+, 2017)J/MNRAS/495/3614 : IR and sub-mm variability in protostars (Contreras+, 2020)J/ApJ/920/132 : NEOWISE 6.5yr variability in YSOs (Park+, 2021)J/AJ/162/101 : K2 ugri & H{alpha} phot. in the Lagoon Nebula (Venuti+, 2021)J/AJ/164/201 : Accretion in 9 Orion OB1b T-Tauri stars (Pittman+, 2022)J/ApJ/935/54 : LDT UBVRI photometry of 14 T-Tauri (Robinson+, 2022)J/ApJ/945/L7 : MIRI MRS sp. of EX Lup taken in quiescence (Kospal+, 2023)http://dasch.cfa.harvard.edu/ : DASCH homepagehttp://www.aavso.org/ : AAVSO homepagehttp://asas-sn.osu.edu/ : ASAS-SN homepagehttp://heasarc.gsfc.nasa.gov/docs/tess/ : NASA TESS Science Support Centerhttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/957/113https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/957/113http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/957/113https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/957/113https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/957/113http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/957/113GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticalInfrareddefaultJ/ApJ/957/113/fig1The full light curve collections of EX Lup; version updated by the authorrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Date of Observation Epochdtime.epochdoubleindexedomag[6.84/15.17] Magnitude in Filtermagphot.magfloate_omag[0.001/99]? Error of omagmagstat.error;phot.magfloatnullableFilterFilter name (1)meta.id;instr.filtercharJ/ApJ/957/113/fig7The multi-color light curves of burst of EX Lup in 2022recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintJDJulian Date of Observation Epochdtime.epochdoubleomag[9.26/14.3] Magnitude in Filtermagphot.magfloate_omag[0.001/0.7] Error of omagmagstat.error;phot.magfloatFilt[UBVRI] Filter name (1)meta.id;instr.filterchar