J/A+A/703/A277ivo://CDS.VizieR/J/A+A/703/A277CDSTesti L.Natta A.Gozzi S.Manara C.F.Williams J.P.Claes R.,Lebreuilly U.Hennebelle P.Klessen R.Molinari S.2026-03-02T06:25:50Z2025-11-25T08:16:08ZCDS support team

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

cds-question@unistra.frprotostarsradio-spectroscopyThe value of the accretion luminosity during the early phases of star formation is crucial information that aids in understanding how stars form, but it is still very difficult to obtain. We have developed a new methodology to measure accretion luminosity using mid-infrared hydrogen recombination lines and applied it to a limited sample of Class I protostars in the Taurus and Ophiuchus star-forming regions. We adopted the commonly used assumption that the properties of disk-protostar accretion in Class I objects is similar to the disk-star accretion in Class II objects. Using simultaneous observations of three hydrogen recombination lines, Br{gamma}, Pf{gamma}, and Br{alpha}, we derived the mean intrinsic line ratios, and we verified that these are constant across the probed range of photospheric and accretion properties. We established correlations between the line luminosities and accretion luminosity. We measured the extinction toward the line emission regions in Class I protostars, comparing the observed line ratios to the Class II mean values. We then derived the Class I accretion luminosities from the established Class II correlations. We find that the accretion luminosity dominates the bolometric luminosity for the more embedded protostars, corresponding to lower values of the bolometric temperature. As the bolometric temperature increases above ~700K, there is a sharp drop of the contribution of the accretion from the bolometric luminosity. Our findings are in qualitative agreement with numerical simulations of star formation. We suggest our methodology be applied to larger and more statistically significant samples of Class I objects to obtain a more detailed comparison. Our results also suggest that by combining multiple infrared line ratios, it will be possible to derive a more detailed description of the dust extinction law in protostellar envelopes.2025A&A...703A.277Thttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/703/A277CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/703/A277https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/703/A277http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/703/A277https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/703/A277https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/703/A277http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/703/A277GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/703/A277/table1 (Class II SpeX data)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A277/table1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A277/table1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A277/table1?GETtext/xml+votable180.050000true64.81597529.10747970.005555555555555556Cone search capability for table J/A+A/703/A277/table2 (Properties of the newly observed Class I/F and those from Beck (2007AJ....133.1673B) (for ID = 18 to 24))https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/703/A277/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/703/A277/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/703/A277/table2?GETtext/xml+votable180.050000true246.5890833-24.38444440.0055555555555555566/1031 1037 1054 1061 1082 1154 1159 1168 1171 28921 42970 42981 42992https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/703/A277?format=asciiMillimeterdefaultJ/A+A/703/A277/table1Class II SpeX dataSimbadSimbad column added by the CDSmeta.ref.urlcharNameNamemeta.id;meta.maincharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintDistDistance are from Gaia EDR3pcpos.distanceintAKExtinctionmagphys.absorptionfloatn_AK[bcd] Note on AK (1)meta.notecharFBrgammaBrgamma flux17W.m**-2phot.fluxfloate_FBrgammaBrgamma flux error17W.m**-2stat.errorfloatl_FPfgammaLimit flag on FPfgammameta.code.errorcharFPfgammaPfgamma flux17W.m**-2phot.fluxfloate_FPfgamma? Pfgamma flux error17W.m**-2stat.errorfloatnullablel_FBralphaLimit flag on FBralphameta.code.errorcharFBralphaBralpha flux17W.m**-2phot.fluxfloate_FBralpha? Bralpha flux error17W.m**-2stat.errorfloatnullablesp[*] * indicates spectra in subdirectory spmeta.notechar_RARight Ascension (J2000) from SIMBAD (not part of the original data)degpos.eq.ra;meta.main_DEDeclination (J2000) from SIMBAD (not part of the original data)degpos.eq.dec;meta.mainJ/A+A/703/A277/table2Properties of the newly observed Class I/F and those from Beck (2007AJ....133.1673B) (for ID = 18 to 24)SimbadNameSimbad column added by the CDSmeta.idcharnullablerecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintIDID numbermeta.idintNameNamemeta.id;meta.maincharRAJ2000Right ascension (J2000)pos.eq.ra;meta.mainDEJ2000Declination (J2000)pos.eq.dec;meta.mainRegionRegionmeta.notecharDistAverage cloud distance for Ophiuchus and average distances of each sub-cloud for Taurus (1)pcpos.distancefloatClassClass (2)src.classcharAKfgForeground absorption in K bandmagphys.absorptionfloatTbolBolometric temperature (3)Kphys.temperatureintE_TbolBolometric temperature error (upper value)Kstat.error;stat.maxinte_TbolBolometric temperature error (lower value)Kstat.errorintLbolBolometric luminosity (3)solLumphys.luminosityfloatE_LbolBolometric luminosity error (upper value)solLumstat.error;stat.maxfloate_LbolBolometric luminosity error (lower value)solLumstat.errorfloatsp[*] * indicates spectra in subdirectory spmeta.notecharJ/A+A/703/A277/listList of spectraLineSpectrum titlemeta.notecharFileNameName of the spectrum file in subdirectory spmeta.id;meta.filecharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintspShow the spectrummeta.ref.urlcharNameNamemeta.id;meta.mainchar