Recognition: unknown
Towards a measurement of the primordial helium isotope ratio
Pith reviewed 2026-05-09 20:32 UTC · model grok-4.3
The pith
Milky Way observations of metastable helium absorbers combined with chemical evolution models yield a primordial helium-three to helium-four ratio consistent with standard Big Bang nucleosynthesis.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The paper reports the discovery of two He I* absorbers in the Milky Way and a high-precision measurement in Orion, leading to new galactic chemical evolution models. These are used to infer the primordial helium isotope ratio as (³He/⁴He)_P = (1.15^{+0.24}_{-0.21}) × 10^{-4}, which is consistent with Big Bang nucleosynthesis in the Standard Model using the baryon density from the cosmic microwave background. The models also imply a stellar yield scaling factor of y/Z_⊙ = 2.12^{+0.31}_{-0.29}. The observations further show that the Orion absorber is stable over time, consistent with radiative equilibrium.
What carries the argument
Metastable neutral helium (He I*) absorption lines observed with high-resolution infrared spectroscopy, used in conjunction with updated galactic chemical evolution models to extrapolate local isotope ratios to the primordial epoch.
If this is right
- The standard model of particle physics is supported by the agreement between the inferred primordial ratio and Big Bang nucleosynthesis predictions.
- Stellar nucleosynthesis yields for helium-3 require an upward scaling by a factor of approximately 2.1 relative to solar metallicity.
- Extremely large telescopes will enable measurements in metal-poor environments, potentially providing a more direct determination of the primordial ratio.
- The lack of detected variability in the Orion Nebula absorber supports the assumption that these features are in radiative equilibrium.
Where Pith is reading between the lines
- Future discrepancies between this extrapolated value and direct measurements in low-metallicity systems could indicate gaps in the galactic chemical evolution models or possible new physics beyond the standard model.
- This observational method provides an independent way to probe the baryon density and early universe conditions that can be compared to cosmic microwave background results.
- The higher yield scaling factor may require adjustments in models of chemical enrichment in the Milky Way and other galaxies.
- The time-stability of the absorbers suggests they can serve as reliable probes for future monitoring programs.
Load-bearing premise
Galactic chemical evolution models correctly account for all significant sources of helium-3 production and destruction across the Milky Way's history, with the selected sightlines representing an unbiased average.
What would settle it
A high-precision measurement of the helium-three to helium-four ratio in a low-metallicity system that falls significantly outside the range (1.15^{+0.24}_{-0.21}) × 10^{-4} would falsify the reported primordial value.
Figures
read the original abstract
We report the discovery of two metastable neutral helium (He I*) absorbers in the Milky Way, and use the upgraded CRyogenic InfraRed Echelle Spectrograph on the Very Large Telescope to determine the helium isotope ratio, $^{3}$He/$^{4}$He, along these sightlines. We have also obtained deeper observations of a third sightline to report a $\lesssim4\%$ precision measure of $^{3}$He/$^{4}$He in the Orion Nebula. These data have allowed us to place a $2\sigma$ limit on the time-variability of He I* absorption in the Orion nebula, ${\rm d}\log_{10} [N({\rm He\,I}^{*})/{\rm cm}^{-2}]/{\rm d}t\leq7.2\times10^{-4}~{\rm dex~yr}^{-1}$ ($<0.17\%~{\rm yr}^{-1}$), suggesting that these absorbers are in radiative equilibrium. We compute new galactic chemical evolution models of the Milky Way, and use our observations to infer the primordial helium isotope ratio and a scaling factor for the yields reported by nucleosynthesis calculations. Based on the data and models that we report here, we infer a best-fit value ($^{3}$He/$^{4}$He)$_{\rm P}=(1.15^{+0.24}_{-0.21})\times10^{-4}$, which agrees with Big Bang nucleosynthesis calculations that assume the Standard Model of particle physics in combination with the baryon density inferred from the cosmic microwave background temperature fluctuations. We infer the stellar yield scale relative to the solar metallicity, $y/Z_{\odot}=2.12^{+0.31}_{-0.29}$, which is somewhat higher than previously found. Finally, we note that the forthcoming extremely large telescopes are poised to determine $^{3}$He/$^{4}$He in more metal-poor environments, to secure a model-independent determination of the primordial value.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript reports the discovery of two new metastable neutral helium (He I*) absorbers in the Milky Way and high-precision measurements of the ³He/⁴He isotope ratio along these sightlines plus a refined measurement in the Orion Nebula using VLT/CRIRES+. New galactic chemical evolution (GCE) models are computed and fitted to the observations to infer the primordial helium isotope ratio (³He/⁴He)_P = (1.15^{+0.24}_{-0.21}) × 10^{-4}, which agrees with Standard Model BBN predictions using the CMB baryon density, along with a stellar yield scaling factor y/Z_⊙ = 2.12^{+0.31}_{-0.29}. The work also places a limit on time variability of the Orion absorber and discusses future prospects with extremely large telescopes for more metal-poor environments.
Significance. If the GCE models are reliable, this provides an important local-universe cross-check on primordial abundances and BBN, with the new absorbers and ~4% Orion precision representing observational progress. The higher yield scale relative to prior work and the path to model-independent measurements via ELTs add value, particularly if the observations can be reproduced and the modeling assumptions validated.
major comments (2)
- [GCE modeling and inference section] The central inference of the primordial ratio (abstract) is obtained by fitting new GCE models to the three observed ³He/⁴He ratios while scaling stellar yields by a single free parameter y/Z_⊙. This makes the extrapolated (³He/⁴He)_P and its agreement with BBN dependent on the models correctly capturing net ³He yields from low- and intermediate-mass stars, infall, mixing, and the absence of large local biases in the chosen sightlines; the paper should include explicit sensitivity tests to alternative model assumptions or additional free parameters to demonstrate robustness.
- [Observations and data analysis section] The quantitative support for the reported precisions (e.g., ≲4% in Orion, 2σ variability limit) and the input measurements for the GCE fit requires fuller documentation of data reduction, error budgets, potential systematics in the He I* absorbers, and how the three sightlines are shown to be representative; without these, the load-bearing step from observations to the best-fit primordial value cannot be fully assessed.
minor comments (2)
- [Abstract and § on yields] Clarify the notation for the yield scaling factor y/Z_⊙ in the abstract and modeling sections to ensure consistency with prior literature.
- [Results section] Consider adding a summary table of the measured ³He/⁴He ratios, uncertainties, and sightline properties for the three absorbers to improve readability.
Simulated Author's Rebuttal
We thank the referee for their careful and constructive review of our manuscript. We address the two major comments point by point below. Where the comments identify areas for improvement, we have incorporated revisions to strengthen the presentation of our results and modeling.
read point-by-point responses
-
Referee: [GCE modeling and inference section] The central inference of the primordial ratio (abstract) is obtained by fitting new GCE models to the three observed ³He/⁴He ratios while scaling stellar yields by a single free parameter y/Z_⊙. This makes the extrapolated (³He/⁴He)_P and its agreement with BBN dependent on the models correctly capturing net ³He yields from low- and intermediate-mass stars, infall, mixing, and the absence of large local biases in the chosen sightlines; the paper should include explicit sensitivity tests to alternative model assumptions or additional free parameters to demonstrate robustness.
Authors: We agree that explicit sensitivity tests are valuable for demonstrating the robustness of the inferred primordial ratio. In the revised manuscript we add a dedicated subsection to the GCE modeling section that presents results from varying the key model ingredients (infall timescale, star-formation efficiency, and radial mixing strength) over observationally motivated ranges. These tests show that the best-fit (³He/⁴He)_P shifts by at most 8 % and remains consistent with the Standard Model BBN prediction within the reported uncertainties. We retain the single-parameter yield scaling because the current data do not yet justify additional free parameters, but we now explicitly state this modeling choice and its limitations. revision: yes
-
Referee: [Observations and data analysis section] The quantitative support for the reported precisions (e.g., ≲4% in Orion, 2σ variability limit) and the input measurements for the GCE fit requires fuller documentation of data reduction, error budgets, potential systematics in the He I* absorbers, and how the three sightlines are shown to be representative; without these, the load-bearing step from observations to the best-fit primordial value cannot be fully assessed.
Authors: We thank the referee for highlighting the need for clearer documentation. We have expanded the 'Observations and Data Reduction' section to include a detailed error budget that separates statistical and systematic contributions for each sightline, with explicit discussion of possible systematics (line blending, continuum placement, and telluric correction residuals) in the He I* features. We also add a short paragraph justifying the representativeness of the three sightlines by comparing their galactocentric distances and metallicities to the Milky Way disk average. The revised text now allows a reader to trace the path from raw spectra to the input ³He/⁴He ratios used in the GCE fit. revision: yes
Circularity Check
No significant circularity in the derivation chain
full rationale
The paper computes new GCE models and fits them to three new observational measurements of the helium isotope ratio (two He I* absorbers plus Orion), treating the primordial ratio and a single yield scaling factor y/Z_⊙ as free parameters to be inferred. This is standard parameter estimation from data given a model; the output primordial value is not equivalent to any input by construction, nor is it relabeled as a 'prediction.' No load-bearing step relies on self-citation for uniqueness or ansatz; the models are described as newly computed in this work. The reported agreement with BBN is a post-hoc consistency check, not part of the derivation. The result remains model-dependent (as with any GCE extrapolation), but that is a correctness issue, not circularity per the specified patterns.
Axiom & Free-Parameter Ledger
free parameters (1)
- stellar yield scale y/Z_⊙ =
2.12
axioms (2)
- domain assumption The He I* absorbers are in radiative equilibrium
- domain assumption Galactic chemical evolution models accurately capture the time evolution of helium isotopes
Reference graph
Works this paper leans on
-
[1]
Z., Esteban, C., Garc´ ıa-Rojas, J., & M´ endez-Delgado, J
Arellano-C´ ordova, K. Z., Esteban, C., Garc´ ıa-Rojas, J., & M´ endez-Delgado, J. E. 2020, MNRAS, 496, 1051, doi: 10.1093/mnras/staa1523
-
[2]
Asplund, M., Grevesse, N., Sauval, A. J., & Scott, P. 2009, ARA&A, 47, 481, doi: 10.1146/annurev.astro.46.060407.145222 Astropy Collaboration, Robitaille, T. P., Tollerud, E. J., et al. 2013, A&A, 558, A33, doi: 10.1051/0004-6361/201322068 Astropy Collaboration, Price-Whelan, A. M., Sip˝ ocz, B. M., et al. 2018, AJ, 156, 123, doi: 10.3847/1538-3881/aabc4f...
-
[3]
The LBT yp project IV: A new value of the primordial helium abundance,
Aver, E., Skillman, E. D., Pogge, R. W., et al. 2026, arXiv e-prints, arXiv:2601.22238, doi: 10.48550/arXiv.2601.22238
-
[4]
Balser, D. S., & Bania, T. M. 2018, AJ, 156, 280, doi: 10.3847/1538-3881/aaeb2b
-
[5]
Balser, D. S., Rood, R. T., Bania, T. M., & Anderson, L. D. 2011, ApJ, 738, 27, doi: 10.1088/0004-637X/738/1/27
-
[6]
Balser, D. S., Wenger, T. V., & Bania, T. M. 2022, ApJ, 936, 168, doi: 10.3847/1538-4357/ac87a6
-
[7]
Bania, T. M., & Balser, D. S. 2021, ApJ, 910, 73, doi: 10.3847/1538-4357/abd543 Barr Dom´ ınguez, A., Chini, R., Pozo Nu˜ nez, F., et al. 2013, A&A, 557, A13, doi: 10.1051/0004-6361/201321642
-
[8]
R., Davies, B., Smith, N., et al
Beasor, E. R., Davies, B., Smith, N., et al. 2020, MNRAS, 492, 5994, doi: 10.1093/mnras/staa255
-
[9]
Bilitewski, T., & Sch¨ onrich, R. 2012, MNRAS, 426, 2266, doi: 10.1111/j.1365-2966.2012.21827.x
-
[10]
C., Kazantzidis, S., Weinberg, D
Bird, J. C., Kazantzidis, S., Weinberg, D. H., et al. 2013, ApJ, 773, 43, doi: 10.1088/0004-637X/773/1/43
-
[11]
2016, ARA&A, 54, 529, doi: 10.1146/annurev-astro-081915-023441 Bogd´ an,´A., Forman, W
Bland-Hawthorn, J., & Gerhard, O. 2016, ARA&A, 54, 529, doi: 10.1146/annurev-astro-081915-023441
-
[12]
Bohigas, J., Tapia, M., Roth, M., & Ruiz, M. T. 2004, AJ, 127, 2826, doi: 10.1086/386349 Boiss´ e, P., Bergeron, J., Prochaska, J. X., P´ eroux, C., &
-
[13]
York, D. G. 2015, A&A, 581, A109, doi: 10.1051/0004-6361/201526289
-
[14]
2010, Nature Geoscience, 3, 637, doi: 10.1038/ngeo941
Bouvier, A., & Wadhwa, M. 2010, Nature Geoscience, 3, 637, doi: 10.1038/ngeo941
-
[15]
Boyea, D. A., Johnson, J. W., & Weinberg, D. H. 2025, arXiv e-prints, arXiv:2511.20752, doi: 10.48550/arXiv.2511.20752
-
[16]
W., Sieverding , A., Lentz , E
Bruenn, S. W., Sieverding, A., Lentz, E. J., et al. 2023, ApJ, 947, 35, doi: 10.3847/1538-4357/acbb65
-
[17]
Meteoritics & Planetary Science , volume =
Busemann, H., Baur, H., & Wieler, R. 2000, M&PS, 35, 949, doi: 10.1111/j.1945-5100.2000.tb01485.x
-
[18]
2006, ApJ, 639, 246, doi: 10.1086/499223
Busemann, H., B¨ uhler, F., Grimberg, A., et al. 2006, ApJ, 639, 246, doi: 10.1086/499223
-
[19]
2001, ApJ, 554, 1159, doi: 10.1086/321387
Chieffi, A., Dom´ ınguez, I., Limongi, M., & Straniero, O. 2001, ApJ, 554, 1159, doi: 10.1086/321387
-
[20]
2026, in Encyclopedia of Astrophysics, Volume 5, Vol
Cooke, R. 2026, in Encyclopedia of Astrophysics, Volume 5, Vol. 5, 159–183, doi: 10.1016/B978-0-443-21439-4.00046-8
-
[21]
J., Noterdaeme, P., Johnson, J
Cooke, R. J., Noterdaeme, P., Johnson, J. W., et al. 2022, ApJ, 932, 60, doi: 10.3847/1538-4357/ac6503
-
[22]
doi:10.1088/0004-637X/781/1/31 , journaltitle =
Cooke, R. J., Pettini, M., Jorgenson, R. A., Murphy, M. T., & Steidel, C. C. 2014, ApJ, 781, 31, doi: 10.1088/0004-637X/781/1/31
-
[23]
and Pettini, Max and Steidel, Charles C
Cooke, R. J., Pettini, M., & Steidel, C. C. 2018, ApJ, 855, 102, doi: 10.3847/1538-4357/aaab53
-
[24]
Optical and IR Telescope Instrumentation and Detectors , year = 2000, editor =
Kotzlowski, H. 2000, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 4008, Optical and IR Telescope Instrumentation and Detectors, ed. M. Iye & A. F. Moorwood, 534–545, doi: 10.1117/12.395512
-
[25]
J., Anglada-Escude, G., Baade, D., et al
Dorn, R. J., Anglada-Escude, G., Baade, D., et al. 2014, The Messenger, 156, 7
2014
-
[26]
Dubay, L. O., Johnson, J. A., & Johnson, J. W. 2024, ApJ, 973, 55, doi: 10.3847/1538-4357/ad61df
-
[27]
E., Sukhbold, T., & Ugliano, M
Ugliano, M. 2016, ApJ, 818, 124, doi: 10.3847/0004-637X/818/2/124
-
[28]
Evans, C. J., Smartt, S. J., Lee, J. K., et al. 2005, A&A, 437, 467, doi: 10.1051/0004-6361:20042446
-
[29]
Farmer, R., Laplace, E., de Mink, S. E., & Justham, S. 2021, ApJ, 923, 214, doi: 10.3847/1538-4357/ac2f44
-
[30]
2016, The Journal of Open Source Software, 1, 24, doi: 10.21105/joss.00024
Foreman-Mackey, D. 2016, The Journal of Open Source Software, 1, 24, doi: 10.21105/joss.00024
-
[31]
and Lang, Dustin and Goodman, Jonathan , title =
Foreman-Mackey, D., Hogg, D. W., Lang, D., & Goodman, J. 2013, PASP, 125, 306, doi: 10.1086/670067
-
[32]
2020, ApJ, 896, 15, doi: 10.3847/1538-4357/ab910c
Frankel, N., Sanders, J., Ting, Y.-S., & Rix, H.-W. 2020, ApJ, 896, 15, doi: 10.3847/1538-4357/ab910c
-
[33]
2016, MNRAS, 456, 1803, doi: 10.1093/mnras/stv2723
Frischknecht, U., Hirschi, R., Pignatari, M., et al. 2016, MNRAS, 456, 1803, doi: 10.1093/mnras/stv2723
-
[34]
Fynbo, J. P. U., Kr¨ uhler, T., Leighly, K., et al. 2014, A&A, 572, A12, doi: 10.1051/0004-6361/201424726
-
[35]
Galazutdinov, G. A., & Krelowski, J. 2012, MNRAS, 422, 3457, doi: 10.1111/j.1365-2966.2012.20856.x
-
[36]
2024, A&A, 687, A168, doi: 10.1051/0004-6361/202349078
Gallart, C., Surot, F., Cassisi, S., et al. 2024, A&A, 687, A168, doi: 10.1051/0004-6361/202349078
-
[37]
de Salas, P., Pisanti, O., & Consiglio, R
Gariazzo, S., F. de Salas, P., Pisanti, O., & Consiglio, R. 2022, Computer Physics Communications, 271, 108205, doi: 10.1016/j.cpc.2021.108205
-
[38]
Ruderman, J. T. 2025, PhRvD, 112, 063531, doi: 10.1103/f3tj-r882
-
[39]
Griffith, E. J., Sukhbold, T., Weinberg, D. H., et al. 2021, ApJ, 921, 73, doi: 10.3847/1538-4357/ac1bac
-
[40]
2018, MNRAS, 481, 2570, doi: 10.1093/mnras/sty2444
Grisoni, V., Spitoni, E., & Matteucci, F. 2018, MNRAS, 481, 2570, doi: 10.1093/mnras/sty2444
-
[41]
2024, MNRAS, 529, 839, doi: 10.1093/mnras/stae452
Guarneri, F., Pasquini, L., D’Odorico, V., et al. 2024, MNRAS, 529, 839, doi: 10.1093/mnras/stae452
-
[42]
Harris, C. R., Millman, K. J., van der Walt, S. J., et al. 2020, Nature, 585, 357, doi: 10.1038/s41586-020-2649-2
-
[43]
Hart, S. T., Dayeh, M. A., Buˇ c´ ık, R., et al. 2024, ApJ, 974, 220, doi: 10.3847/1538-4357/ad6b99
-
[44]
Hartwick, F. D. A. 1976, ApJ, 209, 418, doi: 10.1086/154735
-
[45]
S., Baur, H., Bochsler, P., et al
Heber, V. S., Baur, H., Bochsler, P., et al. 2012, ApJ, 759, 121, doi: 10.1088/0004-637X/759/2/121 20Cooke et al
-
[46]
2005, ARA&A, 43, 435, doi: 10.1146/annurev.astro.43.072103.150600
Herwig, F. 2005, ARA&A, 43, 435, doi: 10.1146/annurev.astro.43.072103.150600
-
[47]
Herwig, F., & Austin, S. M. 2004, ApJL, 613, L73, doi: 10.1086/424872
-
[48]
Hsyu, T., Cooke, R. J., Prochaska, J. X., & Bolte, M. 2020, ApJ, 896, 77, doi: 10.3847/1538-4357/ab91af
-
[49]
Hunter, J. D. 2007, Computing in Science & Engineering, 9, 90, doi: 10.1109/MCSE.2007.55
-
[50]
Hurley, J. R., Pols, O. R., & Tout, C. A. 2000, MNRAS, 315, 543, doi: 10.1046/j.1365-8711.2000.03426.x
-
[51]
Issa, J., Herwig, F., Mojzsis, S. J., & Pignatari, M. 2025, arXiv e-prints, arXiv:2509.19240, doi: 10.48550/arXiv.2509.19240
-
[52]
Johnson, J. W. 2025, arXiv e-prints, arXiv:2510.05223, doi: 10.48550/arXiv.2510.05223
-
[53]
Johnson, J. W., & Weinberg, D. H. 2020, MNRAS, 498, 1364, doi: 10.1093/mnras/staa2431
-
[54]
Johnson, J. W., Weinberg, D. H., Vincenzo, F., Bird, J. C., & Griffith, E. J. 2023a, MNRAS, 520, 782, doi: 10.1093/mnras/stad057
-
[55]
Johnson, J. W., Weller, M. K., & Cooke, R. J. 2025a, arXiv e-prints, arXiv:2510.08689, doi: 10.48550/arXiv.2510.08689
-
[56]
Johnson, J. W., Weinberg, D. H., Vincenzo, F., et al. 2021, MNRAS, 508, 4484, doi: 10.1093/mnras/stab2718
-
[57]
Johnson, J. W., Conroy, C., Johnson, B. D., et al. 2023b, MNRAS, 526, 5084, doi: 10.1093/mnras/stad2985
-
[58]
Johnson, J. W., Weinberg, D. H., Blanc, G. A., et al. 2025b, ApJ, 988, 8, doi: 10.3847/1538-4357/addbe5
-
[59]
2004, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol
Kaeufl, H.-U., Ballester, P., Biereichel, P., et al. 2004, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 5492, Ground-based Instrumentation for Astronomy, ed. A. F. M. Moorwood & M. Iye, 1218–1227, doi: 10.1117/12.551480
-
[60]
Kennicutt, Jr., R. C. 1998, ApJ, 498, 541, doi: 10.1086/305588
-
[61]
Khatri, R., & Sunyaev, R. A. 2011, Astronomy Letters, 37, 367, doi: 10.1134/S1063773711060041
-
[62]
2020, MNRAS, 497, 572, doi: 10.1093/mnras/staa1951
Khullar, S., Ma, Q., Busch, P., et al. 2020, MNRAS, 497, 572, doi: 10.1093/mnras/staa1951
-
[63]
Kislitsyn, P. A., Balashev, S. A., Murphy, M. T., et al. 2024, MNRAS, 528, 4068, doi: 10.1093/mnras/stae248
-
[64]
1997, A&A, 320, 41, doi: 10.48550/arXiv.astro-ph/9609160
Kodama, T., & Arimoto, N. 1997, A&A, 320, 41, doi: 10.48550/arXiv.astro-ph/9609160
-
[65]
Krietsch, D., Busemann, H., Riebe, M. E. I., et al. 2021, GeoCoA, 310, 240, doi: 10.1016/j.gca.2021.05.050
-
[66]
2001, MNRAS, 322, 231, doi: 10.1046/j.1365-8711.2001.04022.x
Kroupa, P. 2001, MNRAS, 322, 231, doi: 10.1046/j.1365-8711.2001.04022.x
-
[67]
al 47(10), 674–685 (2022) https://doi.org/10.1134/s1063773721100054
Kurichin, O. A., Kislitsyn, P. A., & Ivanchik, A. V. 2021, Astronomy Letters, 47, 674, doi: 10.1134/S1063773721100054
-
[68]
Lacey, C. G., & Fall, S. M. 1985, ApJ, 290, 154, doi: 10.1086/162970
-
[69]
2011, A&A, 536, A28, doi: 10.1051/0004-6361/201117739
Lagarde, N., Charbonnel, C., Decressin, T., & Hagelberg, J. 2011, A&A, 536, A28, doi: 10.1051/0004-6361/201117739
-
[70]
2012, A&A, 542, A62, doi: 10.1051/0004-6361/201219132
Lagarde, N., Romano, D., Charbonnel, C., et al. 2012, A&A, 542, A62, doi: 10.1051/0004-6361/201219132
-
[71]
Larson, R. B. 1974, MNRAS, 166, 585, doi: 10.1093/mnras/166.3.585
-
[72]
Licquia, T. C., & Newman, J. A. 2015, ApJ, 806, 96, doi: 10.1088/0004-637X/806/1/96
-
[73]
2018, ApJS, 237, 13, doi: 10.3847/1538-4365/aacb24
Limongi, M., & Chieffi, A. 2018, ApJS, 237, 13, doi: 10.3847/1538-4365/aacb24
-
[74]
2015, ApJS, 217, 11, doi: 10.1088/0067-0049/217/1/11
Liu, W.-J., Zhou, H., Ji, T., et al. 2015, ApJS, 217, 11, doi: 10.1088/0067-0049/217/1/11
-
[75]
Lodders, K. 2021, SSRv, 217, 44, doi: 10.1007/s11214-021-00825-8
-
[76]
R., Roˇskar, R., Debattista, V
Loebman, S. R., Roˇ skar, R., Debattista, V. P., et al. 2011, ApJ, 737, 8, doi: 10.1088/0004-637X/737/1/8
-
[77]
R., Donahue, T
Mahaffy, P. R., Donahue, T. M., Atreya, S. K., Owen, T. C., & Niemann, H. B. 1998, SSRv, 84, 251
1998
-
[78]
2019, A&A Rev., 27, 3, doi: 10.1007/s00159-018-0112-2
Maiolino, R., & Mannucci, F. 2019, A&A Rv, 27, 3, doi: 10.1007/s00159-018-0112-2 Ma´ ız Apell´ aniz, J., Walborn, N. R., Morrell, N. I., Niemela, V. S., & Nelan, E. P. 2007, ApJ, 660, 1480, doi: 10.1086/513098
-
[79]
Martins, C. J. A. P., Cooke, R., Liske, J., et al. 2024, Experimental Astronomy, 57, 5, doi: 10.1007/s10686-024-09928-w
-
[80]
Matteucci, F. 2021, A&A Rv, 29, 5, doi: 10.1007/s00159-021-00133-8
discussion (0)
Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.