J/A+A/708/A22 Accretion diagnostics with JWST/MIRI of YSOs (Shridharan+, 2026)
Improving accretion diagnostics for young stellar objects with mid-infrared
Hydrogen lines from JWST/MIRI.
Shridharan 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.
<Astron. Astrophys. 708, A22 (2026)>
=2026A&A...708A..22S 2026A&A...708A..22S (SIMBAD/NED BibCode)
ADC_Keywords: YSOs ; Stars, nearby ; Spectroscopy ; Infrared sources ;
Line Profiles ; References ; Positional data ; Extinction ;
Mass loss ; Stars, distances
Keywords: accretion, accretion disks - line: identification -
techniques: spectroscopic - protoplanetary disks -
stars: pre-main sequence stars - variables: T Tauri, Herbig Ae/Be
Abstract:
We 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 (5-28µm) and perform LTE slab modelling to
re- move the H2O 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 α (HI 6-5) and Humphreys
α (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
7.502µm and HI (10-7) at 8.760µm 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, nH=1010.6 to 1011.2cm-3 in most stars, with
some stars exhibiting lower densities (<1010cm-3), approaching
the optically thin regime.
Description:
The tablea1.dat contains the fundamental stellar parameters (Distance,
Extinction, Spectral Type) collected from literature or Gaia DR3,
along with reference mass accretion rates. The table2.dat contains the
newly measured line luminosities and derived accretion properties from
publicly available JWST/MIRI observations data.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tablea1.dat 97 79 Stellar parameters of the nearby YSOs
tablea2.dat 175 79 *Measured H I line luminosities, newly derived
accretion luminosities and mass accretion rate
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Note on tablea2.dat: JWST-MIRI log(Lacc) and dMacc/dt values calculated
using the empirical relations established in this work for four H I
transitions: (6-5), (7-6), (8-6), and (10-7). The line luminosity values are
corrected for molecular contamination wherever possible.
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See also:
J/A+A/689/A270 : An all-sky catalogue of stellar reddening values
(Paunzen+, 2024)
J/A+A/667/A124 : GIARPS T Tauri spectra (GHOsT) (Gangi+, 2022)
J/A+A/666/A55 : Accretion variability monitoring in the ONC
(Flaischlen+, 2022)
J/ApJ/653/657 : Spectroscopic observations of Herbig Ae/Be stars
(Manoj+, 2006)
J/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 ρ-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 objects
(Rigliaco+, 2012)
J/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 data
(Michel+, 2021)
J/ApJ/895/38 : MIR extinction toward Cyg OB2-12 ISM (Hensley+, 2020)
J/ApJ/893/56 : T Tauri star IR excesses & Ha eq. widths
(Manzo-Martinez+, 2020)
J/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 Pfβ
(Salyk+, 2013)
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 & RAVE
(Yu+, 2023)
J/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 & mechanisms
(Wichittanakom+ 2020)
J/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 extinction
(Gontcharov+, 2018)
II/366 : ASAS-SN catalog of variable stars (Jayasinghe+, 2018-2020)
Byte-by-byte Description of file: tablea1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Name of the nearby young stars YSO
(Source)
21- 30 F10.6 deg RAdeg Right ascension (J2000) (RA_deg)
32- 40 F9.5 deg DEdeg Declination (J2000) (Dec_deg)
42- 50 A9 --- SpType Spectral types (SpType)
52- 55 I4 --- PropID Observational JWST/MIRI proposal ID
(PropID)
57- 62 F6.2 pc D ? Stellar distance from GaiaDR3 or from
Manara et al. (2023ASPC..534..539M 2023ASPC..534..539M)
(Dist_pc)
64- 68 F5.2 mag AV Optical V-band line of sight extinction
(Av_mag)
70- 76 F7.3 [Msun/yr] log(dM/dt) ? The mass accretion rates from Manara
et al. (2023ASPC..534..539M 2023ASPC..534..539M) (logMacc)
78- 83 F6.3 Lsun L* ? Stellar luminosity (Lstar)
85- 91 F7.4 [Lsun] logLacc ? The accretion luminosity (logLacc)
93- 97 A5 --- Refs Literature references (Refs) (1)
--------------------------------------------------------------------------------
Note (1): Literature references are as follows:
1 = Manara et al. 2023ASPC..534..539M 2023ASPC..534..539M, 31 sources in our sample
2 = Rigliaco et al. 2015ApJ...801...31R 2015ApJ...801...31R, 11 sources in our sample
3 = Herczeg & Hillenbrand 2014ApJ...786...97H 2014ApJ...786...97H, Cat. J/ApJ/786/97,
10 sources in our sample
4 = Salyk et al. 2013ApJ...769...21S 2013ApJ...769...21S, Cat. J/ApJ/769/21, 7 sources
in our sample
5 = Evans et al. 2009ApJS..181..321E 2009ApJS..181..321E, Cat. J/ApJS/181/321, 7 sources
in our sample
6 = Furlan et al. 2009ApJ...703.1964F 2009ApJ...703.1964F, Cat. J/ApJ/703/1964,
7 sources in our sample
7 = Mulders et al. 2017ApJ...847...31M 2017ApJ...847...31M, Cat. J/ApJ/847/31, 8 sources
in our sample
8 = Wichittanakom et al. 2020MNRAS.493..234W 2020MNRAS.493..234W, Cat. J/MNRAS/493/234,
5 sources in our sample
9 = Manara et al. 2014A&A...568A..18M 2014A&A...568A..18M, 1 source in our sample
10 = Manara et 2015A&A...579A..66M 2015A&A...579A..66M, Cat. J/A+A/579/A66, 1 source
in our sample
11 = Dunham et al. 2015ApJS..220...11D 2015ApJS..220...11D, Cat. J/ApJS/220/11, 6 sources
in our sample
12 = Kim et al. 2013ApJ...769..149K 2013ApJ...769..149K, Cat. J/ApJ/769/149, 2 sources
in our sample
13 = Manara et al. 2017A&A...604A.127M 2017A&A...604A.127M, 1 source in our sample
14 = Manoj et al. 2006ApJ...653..657M 2006ApJ...653..657M, Cat. J/ApJ/653/657, 2 sources
in our sample
15 = Michel et al. 2021ApJ...921...72M 2021ApJ...921...72M, Cat. J/ApJ/921/72, 4 sources
in our sample
16 = Gangi et al. 2022A&A...667A.124G 2022A&A...667A.124G, Cat. J/A+A/667/A124, 1 source
in our sample
17 = Garufi et al. 2014A&A...567A.141G 2014A&A...567A.141G, 1 source in our sample
18 = Ribas et al. 2017ApJ...849...63R 2017ApJ...849...63R, Cat. J/ApJ/849/63, 2 sources
in our sample
19 = McDonald et al. 2017MNRAS.471..770M 2017MNRAS.471..770M, Cat. J/MNRAS/471/770, 2
sources in our sample
20 = Salyk et al. 2013ApJ...769...21S 2013ApJ...769...21S, Cat. J/ApJ/769/21, 1 source
in our sample
21 = Gontcharov & Mosenkov 2018MNRAS.475.1121G 2018MNRAS.475.1121G, 2 sources in our
sample
22 = Sullivan et al. 2022AJ....164..100S 2022AJ....164..100S, 2 sources in our sample
23 = Wahhaj et al. 2010ApJ...724..835W 2010ApJ...724..835W, Cat. J/ApJ/724/835, 4 sources
in our sample
24 = Yang et al. 2012ApJ...744..121Y 2012ApJ...744..121Y, Cat. J/ApJ/744/121, 2 sources
in our sample
25 = Alcala et al. 2017A&A...600A..20A 2017A&A...600A..20A, Cat. J/A+A/600/A20, 2 sources
in our sample
26 = Vioque et al. 2018A&A...620A.128V 2018A&A...620A.128V, Cat. J/A+A/620/A128,
2 sources in our sample
27 = Paunzen et al. 2024A&A...689A.270P 2024A&A...689A.270P, Cat. J/A+A/689/A270,
1 source in our sample
28 = Hendler et al. 2017ApJ...841..116H 2017ApJ...841..116H, Cat. J/ApJ/841/116, 1 source
in our sample
29 = Manzo-Martinez et al. 2020ApJ...893...56M 2020ApJ...893...56M, Cat. J/ApJ/893/56,
1 source in our sample
30 = Yu et al. 2023ApJS..264...41Y 2023ApJS..264...41Y, Cat. J/ApJS/264/41, 1 source in
our sample
31 = Fernandes et al. 2023AJ....166..175F 2023AJ....166..175F, Cat. J/AJ/166/175,
1 source in our sample
32 = Luhman & Esplin 2020AJ....160...44L 2020AJ....160...44L, Cat. J/AJ/160/44, 1 source
in our sample
33 = Dahm & Carpenter 2009AJ....137.4024D 2009AJ....137.4024D, 1 source in our sample
34 = Natta et al. 2006A&A...452..245N 2006A&A...452..245N, Cat. J/A+A/452/245, 1 source
in our sample
35 = Jayasinghe et al. 2018MNRAS.477.3145J 2018MNRAS.477.3145J, Cat. II/366, 1 source
in our sample
36 = Fairlamb et al. 2015MNRAS.453..976F 2015MNRAS.453..976F, Cat. J/MNRAS/453/976,
1 source in our sample
-------------------------------------------------------------------------------
Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Name of the nearby young stars YSO
(Source)
21 A1 --- l_logL65 Upper limit of logL65
23- 27 F5.2 [Lsun] logL65 Line luminosity of HI(6-5) transition
at 7.46µm (L65)
29- 32 F4.2 [Lsun] e_logL65 ? Uncertainty of logL65 (errL65)
34 A1 --- l_logL76 Upper limit of logL76
36- 40 F5.2 [Lsun] logL76 Line luminosity of HI(7-6) transition
at 12.37µm (L76)
42- 45 F4.2 [Lsun] e_logL76 ? Uncertainty of logL76 (errL76)
47 A1 --- l_logL86 Upper limit of logL86
49- 53 F5.2 [Lsun] logL86 Line luminosity of HI(8-6) transition
at 7.50µm (L86)
55- 58 F4.2 [Lsun] e_logL86 ? Uncertainty of logL86 (errL86)
60 A1 --- l_logL107 Upper limit of logL107
62- 66 F5.2 [Lsun] logL107 Line luminosity of HI(10-7)
transition at 8.76µm (L107)
68- 71 F4.2 [Lsun] e_logL107 ? Uncertainty of logL107 (errL107)
73 A1 --- l_logLa65 Upper limit of logLa65
75- 79 F5.2 [Lsun] logLa65 Derived accretion luminosity derived
with logL65 (La65)
81- 84 F4.2 [Lsun] e_logLa65 ? Uncertainty of logLa65 (errLa65)
86 A1 --- l_logLa76 Upper limit of logLa76
88- 92 F5.2 [Lsun] logLa76 Derived accretion luminosity derived
with logL76 (La76)
94- 97 F4.2 [Lsun] e_logLa76 ? Uncertainty of logLa76 (errLa76)
99 A1 --- l_logLa86 Upper limit of logLa86
101-105 F5.2 [Lsun] logLa86 Derived accretion luminosity derived
with logL86 (La86)
107-110 F4.2 [Lsun] e_logLa86 ? Uncertainty of logLa86 (errLa86)
112 A1 --- l_logLa107 Upper limit of logLa107
114-118 F5.2 [Lsun] logLa107 Derived accretion luminosity derived
with logL107 (La107)
120-123 F4.2 [Lsun] e_logLa107 ? Uncertainty of logLa107 (errLa107)
125 A1 --- l_log(dMa65/dt) Upper limit of logMa65
127-131 F5.2 [Msun/yr] log(dMa65/dt) ? Derived mass accretion rates
derived with logL65 (Ma65)
133-136 F4.2 [Msun/yr] e_log(dMa65/dt) ? Uncertainty of logMa65 (errMa65)
138 A1 --- l_log(dMa76/dt) Upper limit of logMa76
140-144 F5.2 [Msun/yr] log(dMa76/dt) ? Derived mass accretion rates
derived with logL76 (Ma76)
146-149 F4.2 [Msun/yr] e_log(dMa76/dt) ? Uncertainty of logMa76 (errMa76)
151 A1 --- l_log(dMa86/dt) Upper limit of logMa86
153-157 F5.2 [Msun/yr] log(dMa86/dt) ? Derived mass accretion rates
derived with logL86 (Ma86)
159-162 F4.2 [Msun/yr] e_log(dMa86/dt) ? Uncertainty of logMa86 (errMa86)
164 A1 --- l_log(dMa107/dt) Upper limit of logMa107
166-170 F5.2 [Msun/yr] log(dMa107/dt) ? Derived mass accretion rates
derived with logL107 (Ma107)
172-175 F4.2 [Msun/yr] e_log(dMa107/dt) ? Uncertainty of logMa107 (errMa107)
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Acknowledgements:
Baskaran Shridharan, shridharan.1997(at)gmail.com
(End) Luc Trabelsi [CDS] 04-Dec-2025