J/A+A/551/A107ivo://CDS.VizieR/J/A+A/551/A107doi:10.26093/cds/vizier.35510107CDSManara C.F.Testi L.Rigliaco E.Alcala J.M.Natta A.Stelzer B.,Biazzo K.Covino E.Covino S.Cupani G.D'Elia V.Randich S.2026-01-20T12:10:54Z2014-03-10T15:11:58ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsspectroscopyline-intensitiesThe lack of knowledge of photospheric parameters and the level of chromospheric activity in young low-mass pre-main sequence stars introduces uncertainties when measuring mass accretion rates in accreting (Class II) young stellar objects. A detailed investigation of the effect of chromospheric emission on the estimates of mass accretion rate in young low-mass stars is still missing. This can be undertaken using samples of young diskless (Class III) K and M-type stars. Our is to measure the chromospheric activity of Class III pre main sequence stars to determine its effect on the estimates of the accretion luminosity (Lacc) and mass accretion rate (dMacc/dt) in young stellar objects with disks. Using VLT/X-shooter spectra, we analyzed a sample of 24 nonaccreting young stellar objects of spectral type between K5 and M9.5. We identified the main emission lines normally used as tracers of accretion in Class II objects, and we determined their fluxes in order to estimate the contribution of the chromospheric activity to the line luminosity. We have used the relationships between line luminosity and accretion luminosity derived in the literature for Class II objects to evaluate the impact of chromospheric activity on the accretion rate measurements. We find that the typical chromospheric activity would bias the derived accretion luminosity by L_acc,noise_<10^-3^L_{sun}_, with a strong dependence on the Teff of the objects. The noise on Macc depends on stellar mass and age, and the typical values of log(M_acc,noise_) range between ~-9.2 to -11.6M_{sun}_/yr. Values of L_acc_<10^-3^L_{sun}_ obtained in accreting low-mass pre main sequence stars through line luminosity should be treated with caution because the line emission may be dominated by the contribution of chromospheric activity.2013A&A...551A.107Mhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/551/A107CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/548/A56 : X-shooter spectra of 12 young stellar objects (Rigliaco+, 2012)J/A+A/561/A2 : 36 accreting YSOs emission lines (Alcala+, 2014)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/551/A107https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/551/A107http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/551/A107https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/551/A107https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/551/A107http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/551/A107GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/551/A107/results (All results for the 24 YSOs: literature data (table1), stellar parameters (table3) and spectral types (table4), fluxes and equivalent widths of Balmer (table6), He and Ca lines (table7))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/551/A107/results?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/551/A107/results?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/551/A107/results?GETtext/xml+votable180.050000true177.1009167-37.48031940.0055555555555555566/22851 22854 24608 24716 38191 38363 38687 38742 38800 42611 42614 43545 43575 437047.952274030004205e-20 6.118840631666147e-19https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/551/A107?format=asciidefaultJ/A+A/551/A107/resultsAll results for the 24 YSOs: literature data (table1), stellar parameters (table3) and spectral types (table4), fluxes and equivalent widths of Balmer (table6), He and Ca lines (table7)spUmeta.ref.urlcharspVmeta.ref.urlcharspNmeta.ref.urlcharSp.1MK spectral type obtained using H2O-K2 index (3)src.spTypecharSp.8MK spectral type obtained using sH2Oj index (3)src.spTypecharSp.11MK spectral type obtained using sH2Ok index (3)src.spTypecharSp.9MK spectral type obtained using sH2OH1 index (3)src.spTypecharSp.2MK spectral type obtained using Ij index (3)src.spTypecharSp.3MK spectral type obtained using IH index (3)src.spTypecharSp.12Spectral type obtained using HP index (3)src.spTypecharF(Ha)H{alpha} flux (10^-14^erg/cm^2^/s)aW.m**-2phot.flux;em.line.Halphafloate_F(Ha)rms uncertainty on F(Ha)aW.m**-2stat.errorfloatl_F(3934)Limit flag on F(3934)meta.code.errorcharF(3934)CaII {lambda}393.4 fluxmW.m**-2phot.fluxdoublee_F(3934)? rms uncertainty on F(3934)mW.m**-2stat.errordoublenullablel_F(8499)Limit flag on F(8499)meta.code.errorcharSp.5MK spectral type obtained using H2O index (3)src.spTypecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameSource namemeta.id;meta.maincharONameOther namesmeta.idcharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainRegionRegion: Lup III, TW Hya, or {sigma} Orimeta.noteDistDistance (1)pcpos.distanceintSp.lMK spectral type from literaturesrc.spTypecharUmag? U magnitudemagphot.mag;em.opt.UfloatnullableBmag? B magnitudemagphot.mag;em.opt.BfloatnullableVmag? V magnitudemagphot.mag;em.opt.VfloatnullableRmag? R magnitudemagphot.mag;em.opt.RfloatnullableImag? I magnitudemagphot.mag;em.opt.IfloatnullableJmag? J magnitudemagphot.mag;em.IR.JfloatnullableHmag? H magnitudemagphot.mag;em.IR.HfloatnullableKmag? K magnitudemagphot.mag;em.IR.KfloatnullableRefReferences, in refs.dat filemeta.ref;meta.filecharSpTMK spectral type (2)src.spTypecharTeffEffective temperature (2)Kphys.temperature.effectiveintlog(L*)stellar luminositiylog(solLum)phys.luminosityfloatM*Stellar masssolMassphys.massfloat<Lacc>Average accretion luminosity <log(L_acc,noise_)> (see sec. 6)log(solLum)phys.luminosityfloatUVBUVB (330-550nm) spectrum in subdirectory spmeta.id;meta.filecharVISVIS (550-1000nm) spectrum in subdirectory spmeta.id;meta.filecharNIRNIR (1000-2400nm) spectrum in subdirectory spmeta.id;meta.filecharSlUWidth of the UVB slitarcsecspect.line.widthfloatSlVWidth of the VIS slitarcsecspect.line.widthfloatSlNWidth of the NIR slitarcsecspect.line.widthfloatSp.VMK spectral type obtained using the spectral indices in the VIS part of the spectrum, as explained in Sect. 3.2src.spTypecharl_F(Hb)Limit flag on F(Hb)meta.code.errorcharF(Hb)H{beta} flux (10^-14^erg/cm^2^/s)aW.m**-2phot.flux;em.line.Hbetafloate_F(Hb)? rms uncertainty on F(Hb)aW.m**-2stat.errorfloatnullablel_F(Hg)Limit flag on F(Hg)meta.code.errorcharF(Hg)H{gamma} flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(Hg)? rms uncertainty on F(Hg)aW.m**-2stat.errorfloatnullablel_F(Hd)Limit flag on F(Hd)meta.code.errorcharF(Hd)H{delta} flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(Hd)? rms uncertainty on F(Hd)aW.m**-2stat.errorfloatnullablel_F(H8)Limit flag on F(H8)meta.code.errorcharF(H8)H8 flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(H8)? rms uncertainty on F(H8)aW.m**-2stat.errorfloatnullablel_F(H9)Limit flag on F(H9)meta.code.errorcharF(H9)H9 flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(H9)? rms uncertainty on F(H9)aW.m**-2stat.errorfloatnullablel_F(H10)Limit flag on F(H10)meta.code.errorcharF(H10)H10 flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(H10)? rms uncertainty on F(H10)aW.m**-2stat.errorfloatnullablel_F(H11)Limit flag on F(H11)meta.code.errorcharF(H11)H11 flux (10^-14^erg/cm^2^/s)aW.m**-2phot.fluxfloate_F(H11)? rms uncertainty on F(H11)aW.m**-2stat.errorfloatnullableHa.1H{alpha}10% widthkm/sspect.line.widthfloatBjBalmer jump ratio, intened as F360/F400, (fluxes at ~360nm and ~400nm)phot.flux;arith.ratiofloatW(Ha)? H{alpha} equivalent width0.1nmspect.line.eqWidthfloatnullableW(Hb)? H{beta} equivalent width0.1nmspect.line.eqWidthfloatnullableW(Hg)? H{gamma} equivalent width0.1nmspect.line.eqWidthfloatnullableW(Hd)? H{delta} equivalent width0.1nmspect.line.eqWidthfloatnullableW(H8)? H8 equivalent width0.1nmspect.line.eqWidthfloatnullableW(H9)? H9 equivalent width0.1nmspect.line.eqWidthfloatnullableW(H10)? H10 equivalent width0.1nmspect.line.eqWidthfloatnullableW(H11)? H11 equivalent width0.1nmspect.line.eqWidthfloatnullablel_F(5876)Limit flag on F(5876)meta.code.errorcharF(5876)HeI {lambda}587.6 fluxmW.m**-2phot.fluxdoublee_F(5876)? rms uncertainty on F(5876)mW.m**-2stat.errordoublenullablel_F(10836)Limit flag on HeI2meta.code.errorcharF(10836)HeI {lambda}1083.6 fluxmW.m**-2phot.fluxdoublee_F(10836)? rms uncertainty on F(10836)mW.m**-2stat.errordoublenullableF(8499)CaII {lambda}849.9 fluxmW.m**-2phot.fluxdoublee_F(8499)? rms uncertainty on F(8499)mW.m**-2stat.errordoublenullablel_F(8542)Limit flag on F(8542)meta.code.errorcharF(8542)CaII {lambda}854.2 fluxmW.m**-2phot.fluxdoublee_F(8542)? rms uncertainty on F(8542)mW.m**-2stat.errordoublenullablel_F(8662)Limit flag on F(8662)meta.code.errorcharF(8662)CaII {lambda}866.2 fluxmW.m**-2phot.fluxdoublee_F(8662)? rms uncertainty on F(8662)mW.m**-2stat.errordoublenullableW(5876)? HeI {lambda}587.6 equivalent width0.1nmspect.line.eqWidthfloatnullableW(10836)? HeI {lambda}1083.6 equivalent width0.1nmspect.line.eqWidthfloatnullableW(3934)? CaII {lambda}393.4 equivalent width0.1nmspect.line.eqWidthfloatnullableW(8499)? CaII {lambda}849.9 equivalent width0.1nmspect.line.eqWidthfloatnullableW(8542)? CaII {lambda}854.2 equivalent width0.1nmspect.line.eqWidthfloatnullableW(8662)? CaII {lambda}866.2 equivalent width0.1nmspect.line.eqWidthfloatnullableSimbadNameSimbad column added by the CDSmeta.idnullableJ/A+A/551/A107/tableb1Near-IR spectral indicesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIndexIndex namemeta.id;meta.maincharRangeRange of validityinstr.bandwidthcharNumNumerator [nm]em.wlcharDenDenominator [nm]em.wlcharRefReferencemeta.ref;pos.framecharJ/A+A/551/A107/refsReferencesrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRefReference numbermeta.id;meta.mainintBibCodeBibCodemeta.bib.bibcodecharAutAuthor's namemeta.bib.authorcharComCommentsmeta.notechar