J/A+A/708/A22ivo://CDS.VizieR/J/A+A/708/A22CDSShridharan B.Manoj P.Chandra Pathak V.Caratti o Garatti A.,Banerjee B.Henning T.Kamp I.van Dishoeck E.Tyagi H.Arun R.,Mathew B.Guedel M.Lagage P.-O.2026-03-26T07:44:30Z2026-03-26T08:42:41ZCDS support team

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

cds-question@unistra.fryoung-stellar-objectsspectroscopyinfrared-sourcesastronomical-reference-materialsastrometryextinctionstellar-mass-lossstellar-distanceWe present a comprehensive study of mid-infrared neutral hydrogen (HI) emission lines in 79 nearby (d<200pc) young stars using the James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI). This work extends accretion diagnostics to mid-infrared HI transitions, which are less affected by extinction and outflow emission compared to optical and near-infrared HI lines. We aim to identify mid-infrared HI transitions that can serve as reliable accretion diagnostics in young stars, and evaluate their utility in deriving physical conditions of the accreting gas. We identify and measure 22 HI transitions in the MIRI wavelength regime (5-28{mu}m) and perform LTE slab modelling to re- move the H_2_O contribution from selected HI transitions. We examine the spatial extent of MIR HI emission and assess contamination from molecular and jet-related emission. We find that mid-IR HI line emission is spatially compact, even for sources with spatially extended [NeII] and [FeII] jets, suggesting minimal contamination from extended jet. Although Pfund {alpha} (HI 6-5) and Humphreys {alpha} (HI 7-6) are the strongest lines in the mid-infrared, they are blended with H2O transitions. This blending necessitates additional processing to remove molecular contamination, thereby limiting their use as accretion diagnostics. Instead, we identify the HI (8-6) at 7.502{mu}m and HI (10-7) at 8.760{mu}m transitions as better alternatives, as they are largely unaffected by molecular contamination and offer a more reliable means of measuring accretion rates from MIRI spectra. We provide updated empirical relations for converting mid-IR HI line luminosities into accretion luminosity for 6 different HI lines in the MIRI wavelength range. Moreover, comparison of observed line ratios with theoretical models shows that MIR HI lines offer robust constraints on the hydrogen gas density in accretion columns, n_H_=10^10.6^ to 10^11.2^cm^-3^ in most stars, with some stars exhibiting lower densities (<10^10^cm^-3^), approaching the optically thin regime.2026A&A...708A..22Shttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/708/A22CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/689/A270 : An all-sky catalogue of stellar reddening valuesJ/A+A/667/A124 : GIARPS T Tauri spectra (GHOsT) (Gangi+, 2022)J/A+A/666/A55 : Accretion variability monitoring in the ONCJ/ApJ/653/657 : Spectroscopic observations of Herbig Ae/Be starsJ/A+A/620/A128 : Gaia DR2 study of Herbig Ae/Be stars (Vioque+, 2018)J/A+A/600/A20 : Lupus YSOs X-shooter spectroscopy (Alcala+, 2017)J/A+A/579/A66 : Accretion in {rho}-Ophiucus (Manara+, 2015)J/A+A/570/A82 : Mapping accretion variability in NGC 2264 (Venuti+, 2014)J/A+A/561/A2 : 36 accreting YSOs emission lines (Alcala+, 2014)J/A+A/548/A56 : X-shooter spectra of 12 young stellar objectsJ/A+A/452/245 : Near-IR photometry of PMS stars in rho Oph (Natta+, 2006)J/A+A/365/90 : NIR H lines in TTS (Folha+, 2001)J/ApJ/921/72 : Class II and III disks with Gaia and ALMA dataJ/ApJ/895/38 : MIR extinction toward Cyg OB2-12 ISM (Hensley+, 2020)J/ApJ/893/56 : T Tauri star IR excesses & Ha eq. widthsJ/ApJ/849/63 : FIR-mm data of YSOs in star-forming regions (Ribas+, 2017)J/ApJ/847/31 : Protoplanetary disk data in Cha I and Lupus (Mulders+, 2017)J/ApJ/841/116 : Herschel spectra of 11 very low mass stars (Hendler+, 2017)J/ApJ/786/97 : Photospheric properties of T Tauri stars (Herczeg+, 2014)J/ApJ/769/149 : IR spectroscopy in Orion A: transitional disks (Kim+, 2013)J/ApJ/769/21 : Accretion luminosities of young stars from Pf{beta}J/ApJ/745/19 : Binary systems in Taurus-Auriga (Kraus+, 2012)J/ApJ/744/121 : Far-UV spectroscopy of T Tau stars (Yang+, 2012)J/ApJ/724/835 : The Spitzer c2d survey of WTTSs. III. (Wahhaj+, 2010)J/ApJ/703/1964 : Spectra of three nearby star-forming regions (Furlan+, 2009)J/ApJ/693/L81 : Extinction in star-forming regions (McClure, 2009)J/ApJS/264/41 : Stellar radii & extinctions from APOGEE, GALAH & RAVEJ/ApJS/220/11 : SEDs of Spitzer YSOs in the Gould Belt (Dunham+, 2015)J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)J/AJ/166/175 : Pre- and main sequence stars properties (Fernandes+, 2023)J/AJ/163/174 : IRTF/VLT M-band spectroscopic survey (Banzatti+, 2022)J/AJ/160/44 : Upper Scorpius spectroscopy and photometry (Luhman+, 2020)J/MNRAS/493/234 : Herbig Ae/Be accretion rates & mechanismsJ/MNRAS/471/770 : Parameters and IR excesses of Gaia DR1 stars (McDonald+,2017)J/MNRAS/453/976 : Herbig Ae/Be X-shooter observations (Fairlamb+, 2015)II/354 : HIP and TGAS stars reddening and extinctionII/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/708/A22https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/708/A22http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/708/A22https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/708/A22https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/708/A22http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/708/A22GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/708/A22/tablea1 (Stellar parameters of the nearby YSOs)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/708/A22/tablea1?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/708/A22/tablea1?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/708/A22/tablea1?GETtext/xml+votable180.050000true23.6581111-15.676360.0055555555555555566/1031 1048 1050-1054 1063 1074-1075 1111 1113-1114 1156 1170-1171 17421 21421 23376 23549 23551 24201 28921 29191 30733 30741 36956-36958 37128 38382 41132 42598 42605 42611 42614 42704 42714 42736 42885 42981 42992 43415 44049 44069 44301 44317 44321 44362 44379 44389 45746https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/708/A22?format=asciiInfrareddefaultJ/A+A/708/A22/tablea1Stellar parameters of the nearby YSOsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the nearby young stars YSO (Source)meta.id;meta.maincharRAJ2000Right ascension (J2000) (RA_deg)degpos.eq.ra;meta.mainDEJ2000Declination (J2000) (Dec_deg)degpos.eq.dec;meta.mainSpTypeSpectral types (SpType)src.spTypecharPropIDObservational JWST/MIRI proposal ID (PropID)meta.id;instr.obstyintSimbadNameSimbad column added by the CDSmeta.idcharnullableAVOptical V-band line of sight extinction (Av_mag)magphys.absorption;spect.linefloatD? Stellar distance from GaiaDR3 or from Manara et al. (2023ASPC..534..539M) (Dist_pc)pcpos.distancefloatnullablelog(dM/dt)? The mass accretion rates from Manara et al. (2023ASPC..534..539M) (logMacc)log(solMass.yr**-1)phys.massfloatnullableL*? Stellar luminosity (Lstar)solLumphys.luminosityfloatnullablelogLacc? The accretion luminosity (logLacc)log(solLum)phys.luminosityfloatnullableRefsLiterature references (Refs) (1)meta.ref;pos.framecharJ/A+A/708/A22/tablea2*Measured H I line luminosities, newly derived accretion luminosities and mass accretion ratelogLa107Derived accretion luminosity derived with logL107 (La107)log(solLum)phys.luminosity;em.IR.8-15um;meta.modelledfloate_logLa107? Uncertainty of logLa107 (errLa107)log(solLum)stat.errorfloatnullablel_log(dMa65/dt)Upper limit of logMa65meta.code.errorcharrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintNameName of the nearby young stars YSO (Source)meta.id;meta.maincharl_logL65Upper limit of logL65meta.code.errorcharlogL65Line luminosity of HI(6-5) transition at 7.46{mu}m (L65)log(solLum)phys.luminosity;em.IR.4-8um;spect.linefloate_logL65? Uncertainty of logL65 (errL65)log(solLum)stat.errorfloatnullablel_logL76Upper limit of logL76meta.code.errorcharlogL76Line luminosity of HI(7-6) transition at 12.37{mu}m (L76)log(solLum)phys.luminosity;em.IR.8-15um;spect.linefloate_logL76? Uncertainty of logL76 (errL76)log(solLum)stat.errorfloatnullablel_logL86Upper limit of logL86meta.code.errorcharlogL86Line luminosity of HI(8-6) transition at 7.50{mu}m (L86)log(solLum)phys.luminosity;em.IR.4-8um;spect.linefloate_logL86? Uncertainty of logL86 (errL86)log(solLum)stat.errorfloatnullablel_logL107Upper limit of logL107meta.code.errorcharlogL107Line luminosity of HI(10-7) transition at 8.76{mu}m (L107)log(solLum)phys.luminosity;em.IR.8-15um;spect.linefloate_logL107? Uncertainty of logL107 (errL107)log(solLum)stat.errorfloatnullablel_logLa65Upper limit of logLa65meta.code.errorcharlogLa65Derived accretion luminosity derived with logL65 (La65)log(solLum)phys.luminosity;em.IR.4-8um;meta.modelledfloate_logLa65? Uncertainty of logLa65 (errLa65)log(solLum)stat.errorfloatnullablel_logLa76Upper limit of logLa76meta.code.errorcharlogLa76Derived accretion luminosity derived with logL76 (La76)log(solLum)phys.luminosity;em.IR.8-15um;meta.modelledfloate_logLa76? Uncertainty of logLa76 (errLa76)log(solLum)stat.errorfloatnullablel_logLa86Upper limit of logLa86meta.code.errorcharlogLa86Derived accretion luminosity derived with logL86 (La86)log(solLum)phys.luminosity;em.IR.4-8um;meta.modelledfloate_logLa86? Uncertainty of logLa86 (errLa86)log(solLum)stat.errorfloatnullablel_logLa107Upper limit of logLa107meta.code.errorcharl_log(dMa76/dt)Upper limit of logMa76meta.code.errorcharlog(dMa65/dt)? Derived mass accretion rates derived with logL65 (Ma65)log(solMass.yr**-1)phys.mass;em.IR.4-8um;meta.modelledfloatnullablee_log(dMa65/dt)? Uncertainty of logMa65 (errMa65)log(solMass.yr**-1)stat.errorfloatnullablelog(dMa76/dt)? Derived mass accretion rates derived with logL76 (Ma76)log(solMass.yr**-1)phys.mass;em.IR.8-15um;meta.modelledfloatnullablee_log(dMa76/dt)? Uncertainty of logMa76 (errMa76)log(solMass.yr**-1)stat.errorfloatnullablel_log(dMa86/dt)Upper limit of logMa86meta.code.errorcharlog(dMa86/dt)? Derived mass accretion rates derived with logL86 (Ma86)log(solMass.yr**-1)phys.mass;em.IR.4-8um;meta.modelledfloatnullablee_log(dMa86/dt)? Uncertainty of logMa86 (errMa86)log(solMass.yr**-1)stat.errorfloatnullablel_log(dMa107/dt)Upper limit of logMa107meta.code.errorcharlog(dMa107/dt)? Derived mass accretion rates derived with logL107 (Ma107)log(solMass.yr**-1)phys.mass;em.IR.8-15um;meta.modelledfloatnullablee_log(dMa107/dt)? Uncertainty of logMa107 (errMa107)log(solMass.yr**-1)stat.errorfloatnullable