J/ApJ/956/102ivo://CDS.VizieR/J/ApJ/956/102doi:10.26093/cds/vizier/ba-xw-36CDSHerczeg G.J.Chen Y.Donati J.-F.Dupree A.K.Walter F.M.,Hillenbrand L.A.Johns-Krull C.M.Manara C.F.Gunther H.M.Fang M.,Schneider P.C.Valenti J.A.Alencar S.H.P.Venuti L.Alcala J.M.,Frasca A.Arulanantham N.Linsky J.L.Bouvier J.Brickhouse N.S.,Calvet N.Espaillat C.C.Campbell-White J.Carpenter J.M.Chang S.-J.,Cruz K.L.Dahm S.E.Eisloffel J.Edwards S.Fischer W.J.Guo Z.,Henning T.Ji T.Jose J.Kastner J.H.Launhardt R.Principe D.A.,Robinson C.E.Serna J.Siwak M.Sterzik M.F.Takasao S.2026-02-20T20:01:55Z2026-02-02T14:57:36ZCDS support team

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

cds-question@unistra.frvariable-starsvisible-astronomyspectroscopyextinctionAccretion plays a central role in the physics that governs the evolution and dispersal of protoplanetary disks. The primary goal of this paper is to analyze the stability over time of the mass accretion rate onto TW Hya, the nearest accreting solar-mass young star. We measure veiling across the optical spectrum in 1169 archival high-resolution spectra of TW Hya, obtained from 1998-2022. The veiling is then converted to accretion rate using 26 flux- calibrated spectra that cover the Balmer jump. The accretion rate measured from the excess continuum has an average of 2.51x10^-9^M_{sun}_/yr and a Gaussian distribution with an FWHM of 0.22 dex. This accretion rate may be underestimated by a factor of up to 1.5 because of uncertainty in the bolometric correction and another factor of 1.7 because of excluding the fraction of accretion energy that escapes in lines, especially Ly{alpha}. The accretion luminosities are well correlated with He line luminosities but poorly correlated with H{alpha} and H{beta} luminosity. The accretion rate is always flickering over hours but on longer timescales has been stable over 25 years. This level of variability is consistent with previous measurements for most, but not all, accreting young stars.2023ApJ...956..102Hhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/956/102CatalogResearchIsServedByTAP VizieR generic servicerelated-toIII/174 : High Resolution Atlas of Symbiotic Stars (Van Winckel+ 1993-1994)II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)I/350 : Gaia EDR3 (Gaia Collaboration, 2020)II/362 : i-band variability of YSOs (Sergison+, 2020)J/A+AS/101/485 : Multisite UBVRI photometry in Tau-Aur cloud (Bouvier+ 1993)J/ApJ/686/1195 : IR photometry in the {gamma} Vel cluster (Hernandez+, 2008)J/A+A/504/461 : YSOs in L1630N and L1641 (Fang+, 2009)J/ApJ/745/119 : Close companions to young stars. I. ChaI & Tau (Nguyen+, 2012)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/AJ/147/82 : Monitoring of disk-bearing stars in NGC 2264 (Cody+, 2014)J/ApJ/784/127 : UV spectra of classical T Tauri stars (France+, 2014)J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)J/A+A/592/A83 : HD 100546 and TW Hya model abundances (Kama+, 2016)J/A+A/600/A20 : Lupus YSOs X-shooter spectroscopy (Alcala+, 2017)J/A+A/602/A33 : X-Shooter spectroscopy of YSOs in Lupus (Frasca+, 2017)J/A+A/632/A46 : TW Hydrae association with X-shooter (Venuti+, 2019)J/A+A/643/A99 : DoAr 44 ugri light curves (Bouvier+, 2020)J/AJ/162/101 : K2 ugri & H{alpha} phot. in the Lagoon Nebula (Venuti+, 2021)J/A+A/667/A124 : GIARPS T Tauri spectra (GHOsT) (Gangi+, 2022)J/AJ/163/263 : 323 YSOs properties with ZTF (Hillenbrand+, 2022)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/A+A/672/A5 : GM Aur LCOGT urgi light curves (Bouvier+, 2023)J/AJ/165/269 : TW Hya association candidate members (Luhman, 2023)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/956/102https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/956/102http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/956/102https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/956/102https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/956/102http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/956/102GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapOpticaldefaultJ/ApJ/956/102/table1Summary of instrumentsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSetHRS: high-resolution spectra; or MRS: low- and medium-resolution spectrameta.idcharTelTelescopemeta.id;instr.telcharInstInstrumentmeta.id;instrcharf_InstFlag on Inst (1)meta.codecharlam1[3000/5000] Wavelength lower range in Angstrom0.1nmem.wl;stat.minintlam2[5700/25000] Wavelength upper range in {AA}0.1nmem.wl;stat.maxintf_RangeFlag on Range (1)meta.codecharRes[1000/140000] Resolutionpos.angResolutionintf_ResFlag on Res (1)meta.codecharApertureAperturephys.angSize;instr.fovcharf_ApertureFlag on Aperture (1)meta.codecharSkySky substractioninstr.skyLevelcharNsp[1/467] Number of spectrameta.numberintYearsObserved year(s)time.intervalcharRefInstrument referencemeta.ref;instrcharJ/ApJ/956/102/table5Veiling and accretion measurementsLum[0.008/0.14] LuminositysolLumphys.luminosityfloatrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintMJD[51008.9/59698.2] Modified Julian Datedtime.epochdoubler5050[0.13/2.13] Veiling from 5000-5100{AA}phys.absorption;em.optfloate_r5050[0.002/0.12] Uncertainty in r5050stat.error;phys.absorption;em.optfloatMdot[4.6e-10/7.5e-09] Accretion ratesolMass/yrarith.ratedoubleInstInstrument (1)meta.id;instrcharJ/ApJ/956/102/fig1Coadded ESPaDOnS spectra of TW Hya (see Appendix A)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintlambda[3697.9/10481.5] Wavelength; Angstroms0.1nmem.wldoublef0[-3.32/43.5] Normalized f0 flux density (1)phot.flux;arith.ratiodoublef1[-7.25/38.4] Normalized f1 flux density (1)phot.flux;arith.ratiodoublef2[-7.98/43.9] Normalized f2 flux density (1)phot.flux;arith.ratiodoublef3[-3.57/43.2] Normalized f3 flux density (1)phot.flux;arith.ratiodoublef4[-211/43.6] Normalized f4 flux density (1)phot.flux;arith.ratiodoublef5[-218.3/268] Normalized f5 flux density (1)phot.flux;arith.ratiodoublefresid[-9.21/9.61] Residual spectrum (2)stat.fit.residual;phot.flux;arith.diffdouble