J/A+A/668/A94ivo://CDS.VizieR/J/A+A/668/A94doi:10.26093/cds/vizier.36680094CDSStock C.McGinnis P.Caratti o Garatti A.Natta A.Ray T.P.2023-09-27T06:42:25Z2022-12-08T12:17:44ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsvisible-astronomyspectroscopyline-intensitiesThe process of accretion in classical T Tauri stars (CTTSs) has been observed to vary on different timescales. Studying this variability is vital to understanding a star's evolution and provides insight into the complex processes at work within, including sources of the veiling present. Understanding the dichotomy between continuum veiling and emission line veiling is integral to accurately measuring the amount of veiling present in stellar spectra. Here, 15 roughly consecutive nights of optical spectroscopic data from the spectropolarimeter ESPaDOnS are utilised to characterise the short-term accretion activity in the CTTS, RU Lup, and investigate its relationship with the veiling in the LiI 6707{AA} absorption line. The accretion-tracing HI Balmer series emission lines are studied and used to obtain the accretion luminosity (L_acc_) and mass accretion rate (M_acc_) for each night, which vary by a factor of ~2 between the brightest and dimmest nights. We also measure the veiling using multiple photospheric absorption lines (NaI 5688{AA}, MnI 6021{AA}, and LiI 6707{AA}) for each night. We find the LiI 6707{AA} line provides measurements of veiling that produce a strong, positive correlation with L_acc in the star. When corrected for Li depletion, the average veiling measured in the LiI 6707{AA} line is r_LiI(avg)_=3.25+/-0.20, which is consistent with the other photospheric lines studied (r_avg_=3.28+/-0.65). We measure short timescale variability in the accretion luminosity and mass accretion rate that are intrinsic and not due to geometric effects. As the forbidden line emission we observe ([OI] 6300{AA} and [SII] 6730{AA}) remains remarkably constant over our epochs, it is clear that the variations in the mass accretion rate are too short to have an effect on these outflow-tracers. Upon comparing the changes in veiling and accretion luminosity, we find a strong, positive correlation. This study provides an example of how this correlation can be used as a tool to determine whether a measured variability is due to extinction or an intrinsic change in accretion. As the determination of veiling is an independent process from measuring L_acc, their relationship allows further exploration of accretion phenomena in young stars.2022A&A...668A..94Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/668/A94CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/668/A94https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/668/A94http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/668/A94https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/668/A94https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/668/A94http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/668/A94GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/668/A94/list (List of fits spectra)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/668/A94/list?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/668/A94/list?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/668/A94/list?GETtext/xml+votable180.050000true239.1762917-37.82097220.005555555555555556Associated datahttps://cdsarc.cds.unistra.fr/assocdata/?obs_collection=J/A+A/668/A946/42704https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/668/A94?format=asciiOpticaldefaultJ/A+A/668/A94/table2Accretion luminosities, mass accretion rates veilings from LiI, NaI, and MnI photospheric absorption lines, and the Chi^2^ value of the veiling fit for the LiI linerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintAllDisplay data in all tablesmeta.ref.urlcharObs.DateDate of observation in format YYYY-MM-DDtime.epochnullablelogLaccAccretion luminosity in loglog(solLum)phys.luminosityfloate_logLaccrms the standard deviation (sigma) of the accretion luminositylog(solLum)stat.errorfloatlogMaccMass accretion rate in loglog(solMass.yr**-1)arith.rate;phys.massfloatrNaIVeiling measured in NaI 5688{AA} linemeta.notefloate_rNaIrms error in veiling from NaI linestat.errorfloatrMnI? Veiling measured in MnI 6021{AA} linephys.absorptionfloatnullablee_rMnI? rms error in veiling from MnI linestat.errorfloatnullablerLiobsVeiling measured in LiI 6707{AA} line (observed,pre-abundance correction)phys.absorptionfloatrLiIVeiling measured in LiI 6707{AA} line (post-abundance correction)phys.absorptionfloate_rLiIrms error in veiling from LiI linestat.errorfloatchi2chi^2^ value from the LiI 6707{AA} veiling fitstat.fit.chi2;stat.valuefloatJ/A+A/668/A94/tablea1Integrated fluxes and equivalent widths (EW) of the Halpha, Hbeta, Hgamma and Hdelta emission lines (and their associated errors)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordinte_EWHgrms error in EW of Hgamma0.1nmstat.errorfloatFHdIntegrated flux of the Hdelta 4101{AA} linemW.m**-2phot.flux;spect.linedoublee_FHdrms error in int. flux of Hdelta linemW.m**-2stat.errordoubleObs.dateDate of observation in format YYYY-MM-DDtime.epochnullableFHaIntegrated flux of the Halpha 6562{AA} linemW.m**-2phot.flux;spect.linedoublee_FHarms error in int. flux of Halpha linemW.m**-2stat.errordoubleEWHaEquivalent width of Halpha line0.1nmspect.line.eqWidthfloate_EWHarms error in EW of Halpha0.1nmstat.errorfloatFHbIntegrated flux of the Hbeta 4861{AA} linemW.m**-2phot.flux;spect.linedoublee_FHbrms error in int. flux of Hbeta linemW.m**-2stat.errordoubleEWHbEquivalent width of Hbeta line0.1nmspect.line.eqWidthfloate_EWHbrms error in EW of Hbeta0.1nmstat.errorfloatFHgIntegrated flux of the Hgamma 4340{AA} linemW.m**-2phot.flux;spect.linedoublee_FHgrms error in int. flux of Hgamma linemW.m**-2stat.errordoubleEWHgEquivalent width of Hgamma line0.1nmspect.line.eqWidthfloatEWHdEquivalent width of Hdelta line0.1nmspect.line.eqWidthfloate_EWHdrms error in EW of Hdelta0.1nmstat.errorfloatAllDisplay data in all tablesmeta.ref.urlcharJ/A+A/668/A94/tablea2Integrated fluxes and equivalent widths (EW) of the HeI 5875{AA} and HeI 6678{AA} emission lines (and their associated errors)recnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDateDate of observation in format YYYY-MM-DDtime.epochcharFHeI5875Integrated flux of the HeI 5875{AA} linemW.m**-2phot.flux;spect.linedoublee_FHeI5875rms error in int. flux of HeI 5875{AA} linemW.m**-2stat.errordoubleEWHeI5875Equivalent width of HeI 5875{AA} line0.1nmspect.line.widthfloate_EWHeI5875rms error in EW of HeI 5875{AA}0.1nmstat.errorfloatFHeI6678Integrated flux of the HeI 6678{AA} linemW.m**-2phot.flux;spect.linedoublee_FHeI6678rms error in int. flux of HeI 6678{AA} linemW.m**-2stat.errordoubleEWHeI6678Equivalent width of HeI 6678{AA} line0.1nmspect.line.widthfloate_EWHeI6678rms error in EW of HeI 6678{AA}0.1nmstat.errorfloatAllDisplay data in all tablesmeta.ref.urlcharJ/A+A/668/A94/listList of fits spectraspShow the spectrummeta.ref.urlcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainNxNumber of pixels along X-axismeta.numberintObs.startStart date of observation (MJD)dtime.start;obsdoubleObs.endEnd date of observation (MJD)dtime.end;obsdoublesizeSize of FITS fileKibytephys.size;meta.fitsintFileNameName of FITS file, in subdirectory fitsmeta.id;meta.fitscharTitleTitle of the FITS filemeta.title;meta.fitscharAllDisplay data in all tablesmeta.ref.urlchar