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Carbon and oxygen isotopic ratios

This table compiles isotopic ratio measurements from the literature for various astronomical objects, including directly-imaged exoplanets, brown dwarfs, and stellar companions. Last updated: 2025-09-06

Target Categories:
Super-Jupiter
Young Brown Dwarf
Brown Dwarf
Star
Instruments:
CRIRES+
Keck/NIRSPEC
Keck/KPIC
JWST/NIRSpec
Target Category 12C/13C 16O/18O Instrument Reference Notes
YSES 1 b Super-Jupiter 88 ± 13 — VLT/CRIRES+ Zhang et al. 2024 SupJup III
YSES 1 A Star (K3) 66 ± 5 — VLT/CRIRES+ Zhang et al. 2024 SupJup III
GQ Lup B Super-Jupiter 53+7-6 — VLT/CRIRES+ González Picos et al. 2025 SupJup IV
GQ Lup A Star (K6) 51+10-8 — VLT/CRIRES+ González Picos et al. 2025 SupJup IV
AB Pic b Super-Jupiter 102 ± 8 — VLT/CRIRES+ Gandhi et al. 2025 SupJup V
2MASS J03552337+1133437
(2M0355)		 Young Brown Dwarf 97+25-18 — Keck/NIRSPEC Zhang et al. 2021 —
2MASS J03552337+1133437
(2M0355)		 Young Brown Dwarf 95 ± 7 — VLT/CRIRES+ Grasser et al. 2025 SupJup VIII
2MASS J14252798–3650229
(2M1425)		 Young Brown Dwarf 110+11-10 — VLT/CRIRES+ Grasser et al. 2025 SupJup VIII
TWA 28 Young Brown Dwarf 81+28-19 H218O detection (2.1σ) VLT/CRIRES+ González Picos et al. 2024 SupJup II
TWA 28 Young Brown Dwarf 75 ± 2 683 ± 53 JWST/NIRSpec González Picos et al. in review reanalysis of Manjavacas et al. 2024
TWA 27A Young Brown Dwarf 79+14-11 645+80-70 JWST/NIRSpec González Picos et al. in review reanalysis of Manjavacas et al. 2024
2MASS J08561384-1342242
(J0856)		 Young Brown Dwarf 79+20-14 H218O detection (3.3σ) VLT/CRIRES+ González Picos et al. 2024 SupJup II
2MASS J12003792-7845082
(J1200)		 Young Brown Dwarf 114+69-33 — VLT/CRIRES+ González Picos et al. 2024 SupJup II
2MASS J08354256-0819237
(J0835)		 Young Brown Dwarf 89 ± 11 H218O weak detection VLT/CRIRES+ Mulder et al. 2025 SupJup VI
2MASS J05012406-0010452
(J0501)		 Young Brown Dwarf 117+20-17 — VLT/CRIRES+ Mulder et al. 2025 SupJup VI
2MASS J05002100+0330501
(J0500)		 Young Brown Dwarf 155+56-53 — VLT/CRIRES+ Mulder et al. 2025 SupJup VI
DENIS J025503.3-470049
(J0255)		 Brown Dwarf 184+61-40 — VLT/CRIRES+ de Regt et al. 2024 SupJup I
HIP 55507 A Star (K6) 79+21-16 288+125-70 Keck/NIRSPEC Xuan et al. 2024 —
HIP 55507 B Star (M7) 98+28-22 240+145-80 Keck/NIRSPEC Xuan et al. 2024 —
GQ Lup B Super-Jupiter 153+43-21 — Keck/KPIC Xuan et al. 2024 —
HIP 79098 b Super-Jupiter 52+22-17 — Keck/KPIC Xuan et al. 2024 —
DH Tau b Super-Jupiter 53+50-24 — Keck/KPIC Xuan et al. 2024 —
WISEPA J182831.08+265037.8
(WISE 1828)		 Brown Dwarf >40 — JWST/NIRSpec Lew et al. 2024 Y dwarf
2MASS J04151954-0935066
(2MASS 0415-0935)		 Brown Dwarf 97+9-8 — JWST/NIRSpec Hood et al. 2024 T dwarf; preprint
2MASS J04151954-0935066
(2MASS 0415-0935)		 Brown Dwarf 87 ± 5 481+68-58 JWST/NIRSpec Gonzalez Picos et al. in prep. T dwarf; dataset from Hood et al. 2024
HD 19467 B Brown Dwarf 155+19-15 683+170-113 JWST/NIRSpec Gonzalez Picos et al. in prep. T dwarf; dataset from Ruffio et al. 2023
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Notes:

  • Uncertainties are shown as superscript/subscript when asymmetric, otherwise as ± for symmetric errors
  • Dashes (—) indicate no measurement reported or detection below significance threshold
  • Detection significance levels are noted in parentheses where applicable
  • DOI links provide direct access to the original publications

Missing measurements? If you have isotopic ratio measurements that should be included in this compilation, please contact me at picos@strw.leidenuniv.nl.