J/A+A/704/A42ivo://CDS.VizieR/J/A+A/704/A42CDSFiorellino E.Alcala J.M.Manara C.F.Pittman C.V.Abraham P.,Venuti L.Cabrit S.Claes R.Fang M.Kospal A.Lodato G.Mauco K.,Tychoniec L.2026-03-02T06:25:50Z2025-12-05T09:16:48ZCDS support team

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

cds-question@unistra.frpre-main-sequence-starsaccretionvisible-astronomyThe accretion luminosity (Lacc) in young, low-mass stars is crucial for understanding stellar formation. However, obtaining direct measurements is often hindered by limited spectral coverage and challenges in UV-excess modeling. Empirical relations linking Lacc to various accretion tracers are widely used to overcome these limitations. This work revisits these empirical relations using the PENELLOPE dataset, evaluating their applicability across different starforming regions as well as accreting young objects other than Classical T Tauri Stars (CTTSs; Class II sources). We analyzed the PENELLOPE VLT/X-shooter dataset of 64 CTTSs, measuring fluxes of several accretion tracers and adopting the stellar and accretion parameters derived from studies based on PENELLOPE. For 61 sources, we supplemented our analysis with the ODYSSEUS HST data set, which covers a wider spectral range in NUV bands. We compared the Lacc values obtained in the PENELLOPE and ODYSSEUS surveys, which employed a single hydrogen slab model (XS-fit) and a multi-column accretion shock model (HST-fit), respectively, and found statistically consistent results. Our analysis confirms that existing empirical relations, previously derived for the Lupus sample, provide reliable Lacc estimates for CTTSs in several other star-forming regions. We revisit empirical relations for accretion tracers in our dataset, based on HST-fit, with coefficients which are consistent within 1{sigma} with XS-fit results for most lines. We also propose a method to estimate extinction using these relations and investigate the empirical relations for Brackett lines (Br8 to Br21). The Lacc-Lline empirical relations can be successfully used for statistical studies of accretion on young forming objects in different star-forming regions. These relations also offer a promising approach to independently estimate extinction in CTTSs, provided a sufficient number of flux-calibrated tracers are available across a broad spectral range. We confirm that near-infrared lines (Pa{beta} and Br{gamma}) serve as reliable tracers of Lacc in high accretors, making them valuable tools for probing accretion properties of high accreting young stars not accessible in the UVB.2025A&A...704A..42Fhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/704/A42CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/704/A42https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/704/A42http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/704/A42https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/704/A42https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/704/A42http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/704/A42GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/704/A42/tablea1 (The PENELLOPE sample)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/704/A42/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/704/A42/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/704/A42/tablea1?GETtext/xml+votable180.050000true82.3469167-1.42097220.0055555555555555566/1029 1048 1073 1083 1170 22851 22854 22861-22862 22874 22881 22884 23549 36956-36958 37012-37013 37128 41472 42598 42605 42611 42614-42615 42704-42705 42713-42714 42727 42736-42737 47826 47845https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/704/A42?format=asciiOpticaldefaultJ/A+A/704/A42/tablea1The PENELLOPE samplerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintRegionStar Forming Region (Region)meta.idcharNameName of the Source (Name)meta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainAvWExtinction computed using the weighted coefficient method (Av_W)magobs.atmos.extinctionfloate_AvWLower error on AvW (dAv_Wminus)magstat.errorfloatE_AvWUpper error on AvW (dAv_Wplus)magstat.error;stat.maxfloatlogLaccWlogarithm of the accretion luminosity computed using line fluxes dereddened with AvW (logLacc_W)log(solLum)phys.luminosityfloate_logLaccWError on logLaccW (dlogLacc_W)log(solLum)stat.errorfloatAvnotWExtinction computed using the unweighted coefficient method (Av_notW)magobs.atmos.extinctionfloate_AvnotWLower error on AvnotW (dAv_notWminus)magstat.errorfloatE_AvnotWUpper error on AvnotW (dAv_notWplus)magstat.error;stat.maxfloatlogLaccnotWlogarithm of the accretion luminosity computed using line fluxes dereddened with AvnotW (logLacc_notW)log(solLum)phys.luminosityfloate_logLaccnotWError on logLaccnotW (dlogLacc_notW)log(solLum)stat.errorfloatAvdiffExtinction computed using the difference method (Av_diff)magphys.absorption;arith.difffloate_AvdiffLower error on Avdiff (dAv_diff_minus)magstat.errorfloatE_AvdiffUpper error on Avdiff (dAv_diff_plus)magstat.error;stat.maxfloatlogLaccdifflogarithm of the accretion luminosity computed using line fluxes dereddened with Av_diff (logLacc_diff)log(solLum)phys.luminosityfloatSimbadNameSimbad column added by the CDSmeta.idcharnullablee_logLaccdiffError on logLaccdiff (dlogLacc_diff)log(solLum)stat.errorfloatdeltaT? Time interval between HST and XS observation of the target (deltaT)dobs.param;obsfloatnullable