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arxiv: 2606.19487 · v1 · pith:BV3LRHQKnew · submitted 2026-06-17 · 🌌 astro-ph.EP

Atmospheric asymmetries in WASP-121 b revealed by rotational transits detected with JWST

Cyril Gapp , Aur\'elien Falco , Thomas M. Evans-Soma , David K. Sing , Shashank Dholakia , Vivien Parmentier , J\'er\'emy Leconte , Eva-Maria Ahrer
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Guangwei Fu
This is my paper

Pith reviewed 2026-06-26 19:04 UTC · model grok-4.3

classification 🌌 astro-ph.EP
keywords exoplanet atmospherestransmission spectroscopyultra-hot JupitersJWSTWASP-121 batmospheric dynamicsrotational effects
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The pith

Two transits of WASP-121 b show asymmetric light curves from the planet's rotation, with rising CO absorption indicating higher eastern dayside temperatures.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper establishes that the planet's spin during transit brings successive atmospheric regions across the terminator into view, producing measurable changes in the transmission spectrum. CO absorption increases while H2O absorption slightly decreases, pointing to a steeper east-west temperature contrast on the evening side than on the morning side. A sympathetic reader would care because this supplies a direct observational handle on longitudinal atmospheric structure in tidally locked planets, beyond the usual morning-evening terminator split. The pattern matches expectations for thermal dissociation of water at higher eastern temperatures while CO stays abundant.

Core claim

The central claim is that the two observed transits exhibit asymmetric light curves caused by WASP-121 b's rotation, with the transmission spectrum showing increasing CO absorption and slightly decreasing H2O absorption as the planet rotates; these changes indicate a stronger longitudinal temperature gradient across the evening terminator than the morning terminator, consistent with higher temperatures in the eastern half than the western half of the dayside.

What carries the argument

Rotational transit, the effect in which the planet's spin during the transit progressively exposes different longitudinal slices of its atmosphere to the line of sight.

If this is right

  • The evening terminator exhibits a stronger longitudinal temperature gradient than the morning terminator.
  • Higher eastern dayside temperatures drive thermal dissociation of H2O while leaving CO largely intact.
  • Longitudinal gradients of temperature and chemistry can be constrained from rotational phase coverage during a single transit.
  • This provides a probe of atmospheric heterogeneity that is distinct from limb-asymmetry measurements between morning and evening terminators.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Similar rotational signatures may be detectable in other ultra-hot Jupiters observed with JWST at high cadence.
  • Ignoring rotational effects could bias retrievals of average terminator properties when phase coverage is good.
  • Multi-transit campaigns could map the full dayside temperature distribution by stacking rotational signals.

Load-bearing premise

The observed changes in transmission spectrum with orbital phase are produced by the planet's rotation bringing different atmospheric regions into view rather than by instrumental systematics or orbital dynamics.

What would settle it

A third transit or re-reduction of the existing data that shows no phase-dependent change in CO or H2O absorption depths, or that reproduces the asymmetry with a model containing only instrumental or limb-darkening effects.

read the original abstract

Close-in exoplanets are tidally locked to their host star and thus exhibit extreme atmospheric temperature gradients. It has been theorized that the fraction of star light absorbed by such planets during transit changes as a function of orbital phase as progressively hotter or colder atmospheric gas rotates into view, but this effect has not been observed so far. Here, we show that two transits of the ultra-hot Jupiter WASP-121 b, acquired with JWST/NIRSpec and NIRISS, exhibit asymmetric transit light curves caused by the planet's rotation during transit. We observe increasing CO absorption and slightly decreasing H$_2$O absorption in the transmission spectrum, as the planet rotates. These results are indicative of a stronger longitudinal temperature gradient across the evening than across the morning terminator, consistent with higher temperatures in the eastern half than in the western half of the dayside. The observed changes of the transmission spectrum with orbital phase are in line with the temperature increase causing thermal dissociation of H$_2$O, while CO remains abundant. The observation of longitudinal gradients of atmospheric temperature and chemistry from the planet's rotational transit provides a new probe for constraining atmospheric heterogeneity using JWST beyond differences between morning and evening terminators from limb asymmetries.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 3 minor

Summary. The paper claims detection of asymmetric transit light curves in two JWST/NIRSpec and NIRISS observations of WASP-121 b, attributed to the planet's rotation during transit bringing different longitudes into view. It reports increasing CO absorption and slightly decreasing H2O absorption with orbital phase, interpreted as evidence for a stronger longitudinal temperature gradient across the evening terminator than the morning one, consistent with higher eastern dayside temperatures and thermal dissociation of H2O while CO remains stable. This is presented as a new probe of atmospheric heterogeneity beyond standard limb asymmetries.

Significance. If the attribution of the asymmetries and spectral changes specifically to rotational effects holds after rigorous testing, the result would be significant for the field: it demonstrates a novel JWST-accessible method to constrain east-west atmospheric gradients and chemistry in tidally locked ultra-hot Jupiters, providing empirical tests of 3D circulation and dissociation models that were previously only theoretical.

major comments (2)
  1. [Abstract and §3] Abstract and §3 (light-curve analysis): the central claim that the observed transit asymmetries are caused by planetary rotation (rather than residual JWST systematics, limb-darkening inaccuracies, or orbital geometry effects) is load-bearing but lacks quantitative demonstration that the asymmetry amplitude matches the expected rotational contribution given the known spin period and scale height; without this, the causal link remains at risk.
  2. [§4] §4 (transmission spectra): the interpretation of phase-dependent CO increase / H2O decrease as indicating a stronger evening-terminator gradient requires forward-modeling comparisons showing that the observed spectral changes exceed those expected from unmodeled limb asymmetries or chemistry variations unrelated to the claimed east-west dayside gradient; the current evidence appears post-hoc.
minor comments (3)
  1. Clarify the exact orbital phases of the two transits and the binning choices for the phase-resolved spectra to allow reproducibility.
  2. Add explicit references to prior theoretical work on rotational transit effects in ultra-hot Jupiters for context.
  3. Ensure error bars on the reported absorption changes account for correlated noise in the JWST time series.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their constructive comments. We address each major comment below and indicate planned revisions to strengthen the manuscript.

read point-by-point responses

  1. Referee: [Abstract and §3] Abstract and §3 (light-curve analysis): the central claim that the observed transit asymmetries are caused by planetary rotation (rather than residual JWST systematics, limb-darkening inaccuracies, or orbital geometry effects) is load-bearing but lacks quantitative demonstration that the asymmetry amplitude matches the expected rotational contribution given the known spin period and scale height; without this, the causal link remains at risk.

    Authors: We agree that a quantitative demonstration is important to solidify the attribution to rotation. In the revised manuscript we will add to §3 an explicit calculation of the expected asymmetry amplitude using the known spin period, transit duration, and scale height of WASP-121 b. This will show that the observed asymmetry is consistent in magnitude with the rotational contribution, helping to distinguish it from systematics or geometric effects. revision: yes

  2. Referee: [§4] §4 (transmission spectra): the interpretation of phase-dependent CO increase / H2O decrease as indicating a stronger evening-terminator gradient requires forward-modeling comparisons showing that the observed spectral changes exceed those expected from unmodeled limb asymmetries or chemistry variations unrelated to the claimed east-west dayside gradient; the current evidence appears post-hoc.

    Authors: We acknowledge the value of forward-modeling comparisons. While a full 3D forward model lies beyond the present scope, the revised §4 will include a semi-quantitative estimate showing that the observed CO increase and H2O decrease exceed the amplitude expected from limb asymmetries alone and align with the expected effects of a stronger evening-terminator temperature gradient and H2O dissociation. This addition will make the interpretation less post-hoc. revision: partial

Circularity Check

0 steps flagged

No significant circularity; claims are observational interpretations of JWST data

full rationale

The paper reports direct JWST observations of asymmetric transit light curves and phase-dependent spectral changes in WASP-121 b, attributing them to rotational effects via comparison with expected atmospheric gradients. No derivation chain, equations, or predictions reduce to inputs by construction; there are no self-definitional parameters, fitted inputs renamed as predictions, or load-bearing self-citations that force the result. The interpretation rests on external physical expectations rather than internal redefinition, qualifying as self-contained empirical analysis.

Axiom & Free-Parameter Ledger

0 free parameters · 2 axioms · 0 invented entities

The central claim rests on standard domain assumptions about tidally locked planets and high-temperature molecular chemistry; no free parameters or invented entities are introduced in the abstract.

axioms (2)
  • domain assumption Close-in exoplanets are tidally locked and exhibit extreme atmospheric temperature gradients.
    Invoked in the first sentence of the abstract as the physical basis for the expected rotational effect.
  • domain assumption Temperature increase causes thermal dissociation of H2O while CO remains abundant.
    Used to interpret the observed increase in CO and decrease in H2O absorption.

pith-pipeline@v0.9.1-grok · 5791 in / 1247 out tokens · 20008 ms · 2026-06-26T19:04:06.203938+00:00 · methodology

discussion (0)

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Works this paper leans on

79 extracted references · 5 canonical work pages

  1. [1]

    & Sasselov, D

    Seager, S. & Sasselov, D. D. Theoretical Transmission Spectra during Extrasolar Giant Planet Transits.Astrophys. J.537, 916–921 (2000)

    2000

  2. [2]

    Astrophys.623, A161 (2019)

    Caldas, A.et al.Effects of a fully 3D atmospheric structure on exoplanet trans- mission spectra: retrieval biases due to day-night temperature gradients.Astron. Astrophys.623, A161 (2019)

    2019

  3. [3]

    & Pluriel, W

    Falco, A., Leconte, J., Mechineau, A. & Pluriel, W. Signature of the atmospheric asymmetries of hot and ultra-hot Jupiters in light curvest.Astron. Astrophys. 685, A125 (2024)

    2024

  4. [4]

    Burrows, A., Rauscher, E., Spiegel, D. S. & Menou, K. Photometric and Spec- tral Signatures of Three-dimensional Models of Transiting Giant Exoplanets. Astrophys. J. Lett.719, 341–350 (2010)

    2010

  5. [5]

    P., Parmentier, V

    Wardenier, J. P., Parmentier, V. & Lee, E. K. H. All along the line of sight: a closer look at opening angles and absorption regions in the atmospheres of transiting exoplanets.Mon. Not. R. Astron. Soc.510, 620–629 (2022)

    2022

  6. [6]

    Nature580, 597–601 (2020)

    Ehrenreich, D.et al.Nightside condensation of iron in an ultrahot giant exoplanet. Nature580, 597–601 (2020)

    2020

  7. [7]

    Kesseli, A. Y. & Snellen, I. A. G. Confirmation of Asymmetric Iron Absorption in WASP-76b with HARPS.Astrophys. J. Lett.908, L17 (2021). 19

    2021

  8. [8]

    J.165, 242 (2023)

    Gandhi, S.et al.Retrieval Survey of Metals in Six Ultrahot Jupiters: Trends in Chemistry, Rain-out, Ionization, and Atmospheric Dynamics.Astron. J.165, 242 (2023)

    2023

  9. [9]

    Y., Snellen, I

    Kesseli, A. Y., Snellen, I. A. G., Casasayas-Barris, N., Molli` ere, P. & S´ anchez- L´ opez, A. An Atomic Spectral Survey of WASP-76b: Resolving Chemical Gradients and Asymmetries.Astrophys. J.163, 107 (2022)

    2022

  10. [10]

    Gandhi, S.et al.Spatially resolving the terminator: variation of Fe, temperature, and winds in WASP-76 b across planetary limbs and orbital phase.Mon. Not. R. Astron. Soc.515, 749–766 (2022)

    2022

  11. [11]

    B.et al.No Umbrella Needed: Confronting the Hypothesis of Iron Rain on WASP-76b with Post-processed General Circulation Models.Astrophys

    Savel, A. B.et al.No Umbrella Needed: Confronting the Hypothesis of Iron Rain on WASP-76b with Post-processed General Circulation Models.Astrophys. J. 926, 85 (2022)

    2022

  12. [12]

    Astrophys.687, A49 (2024)

    Maguire, C.et al.High resolution atmospheric retrievals of WASP-76b transmis- sion spectroscopy with ESPRESSO: Monitoring limb asymmetries across multiple transits.Astron. Astrophys.687, A49 (2024)

    2024

  13. [13]

    P., Parmentier, V., Lee, E

    Wardenier, J. P., Parmentier, V., Lee, E. K. H., Line, M. R. & Gharib-Nezhad, E. Decomposing the iron cross-correlation signal of the ultra-hot Jupiter WASP-76b in transmission using 3D Monte Carlo radiative transfer.Mon. Not. R. Astron. Soc.506, 1258–1283 (2021)

    2021

  14. [14]

    V.et al.Vertical structure of an exoplanet’s atmospheric jet stream

    Seidel, J. V.et al.Vertical structure of an exoplanet’s atmospheric jet stream. Nature639, 902–908 (2025)

    2025

  15. [15]

    P.et al.Phase-resolving the Absorption Signatures of Water and Carbon Monoxide in the Atmosphere of the Ultra-hot Jupiter WASP-121b with GEMINI-S/IGRINS.Publ

    Wardenier, J. P.et al.Phase-resolving the Absorption Signatures of Water and Carbon Monoxide in the Atmosphere of the Ultra-hot Jupiter WASP-121b with GEMINI-S/IGRINS.Publ. Astron. Soc. Pac.136, 084403 (2024)

    2024

  16. [16]

    P.et al.Atmospheric Circulation of Hot Jupiters: Coupled Radiative-Dynamical General Circulation Model Simulations of HD 189733b and HD 209458b.Astrophys

    Showman, A. P.et al.Atmospheric Circulation of Hot Jupiters: Coupled Radiative-Dynamical General Circulation Model Simulations of HD 189733b and HD 209458b.Astrophys. J.699, 564–584 (2009)

    2009

  17. [17]

    Astrophys.617, A110 (2018)

    Parmentier, V.et al.From thermal dissociation to condensation in the atmo- spheres of ultra hot Jupiters: WASP-121b in context.Astron. Astrophys.617, A110 (2018)

    2018

  18. [18]

    batman: BAsic Transit Model cAlculatioN in Python.Publ

    Kreidberg, L. batman: BAsic Transit Model cAlculatioN in Python.Publ. Astron. Soc. Pac.127, 1161 (2015)

    2015

  19. [19]

    & Jones, K

    Espinoza, N. & Jones, K. Constraining Mornings and Evenings on Distant Worlds: A new Semianalytical Approach and Prospects with Transmission Spectroscopy. Astron. J.162, 165 (2021). 20

    2021

  20. [20]

    & Wakeford, H

    Grant, D. & Wakeford, H. R. Transmission strings: a technique for spatially mapping exoplanet atmospheres around their terminators.Mon. Not. R. Astron. Soc.519, 5114–5127 (2023)

    2023

  21. [21]

    Mikal-Evans, T.et al.A JWST NIRSpec Phase Curve for WASP-121b: Dayside Emission Strongest Eastward of the Substellar Point and Nightside Conditions Conducive to Cloud Formation.Astrophys. J. Lett.943, L17 (2023)

    2023

  22. [22]

    M.et al.SiO and a super-stellar C/O ratio in the atmosphere of the giant exoplanet WASP-121 b.Nat

    Evans-Soma, T. M.et al.SiO and a super-stellar C/O ratio in the atmosphere of the giant exoplanet WASP-121 b.Nat. Astron.9, 845–861 (2025)

    2025

  23. [23]

    J.169, 341 (2025)

    Gapp, C.et al.WASP-121 b’s Transmission Spectrum Observed with JWST/NIRSpec G395H Reveals Thermal Dissociation and SiO in the Atmo- sphere.Astron. J.169, 341 (2025)

    2025

  24. [24]

    J.170, 323 (2025)

    Splinter, J.et al.Precise Constraints on the Energy Budget of WASP-121 b from Its JWST NIRISS/SOSS Phase Curve.Astron. J.170, 323 (2025)

    2025

  25. [25]

    Commun.16, 10822 (2025)

    Allart, R.et al.A complex structure of escaping helium spanning more than half the orbit of the ultra-hot Jupiter WASP-121 b.Nat. Commun.16, 10822 (2025)

    2025

  26. [26]

    P., Sing, D

    Thorngren, D. P., Sing, D. K. & Mukherjee, S. Bayesian Model Comparison and Significance: Widespread Errors and How to Correct Them.Astrophys. J. Suppl. Ser.283, 10 (2026)

    2026

  27. [27]

    Winn, J. N. inExoplanet Transits and Occultations(ed.Seager, S.)Exoplanets 55–77 (University of Arizona Press, Tucson, AZ, USA, 2010)

    2010

  28. [28]

    Mikal-Evans, T.et al.Confirmation of water emission in the dayside spectrum of the ultrahot Jupiter WASP-121b.Mon. Not. R. Astron. Soc.496, 1638–1644 (2020)

    2020

  29. [29]

    Smith, P. C. B.et al.The Roasting Marshmallows Program with IGRINS on Gemini South. II. WASP-121 b has Superstellar C/O and Refractory-to-volatile Ratios.Astron. J.168, 293 (2024)

    2024

  30. [30]

    J.169, 10 (2025)

    Pelletier, S.et al.CRIRES + and ESPRESSO Reveal an Atmosphere Enriched in Volatiles Relative to Refractories on the Ultrahot Jupiter WASP-121b.Astron. J.169, 10 (2025)

    2025

  31. [31]

    Astrophys.645, A24 (2021)

    Borsa, F.et al.Atmospheric Rossiter-McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO.Astron. Astrophys.645, A24 (2021)

    2021

  32. [32]

    P., Parmentier, V., Line, M

    Wardenier, J. P., Parmentier, V., Line, M. R. & Lee, E. K. H. Modelling the effect of 3D temperature and chemistry on the cross-correlation signal of transiting ultra-hot Jupiters: a study of five chemical species on WASP-76b.Mon. Not. R. 21 Astron. Soc.525, 4942–4961 (2023)

    2023

  33. [33]

    Kempton, E. M. R.et al.A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization.Publ. Astron. Soc. Pac.130, 114401 (2018)

    2018

  34. [34]

    & Dholakia, S

    Dholakia, S., Luger, R. & Dholakia, S. Efficient and Precise Transit Light Curves for Rapidly Rotating, Oblate Stars.Astrophys. J.925, 185 (2022)

    2022

  35. [35]

    Astrophys.659, A74 (2022)

    Deline, A.et al.The atmosphere and architecture of WASP-189 b probed by its CHEOPS phase curve.Astron. Astrophys.659, A74 (2022)

    2022

  36. [36]

    P.et al.KELT-9 b’s Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin-Orbit Misalignment.Astron

    Ahlers, J. P.et al.KELT-9 b’s Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin-Orbit Misalignment.Astron. J.160, 4 (2020)

    2020

  37. [37]

    L.et al.The NASA Exoplanet Archive and Exoplanet Follow-up Observing Program: Data, Tools, and Usage.Planet

    Christiansen, J. L.et al.The NASA Exoplanet Archive and Exoplanet Follow-up Observing Program: Data, Tools, and Usage.Planet. Sci. J.6, 186 (2025)

    2025

  38. [38]

    K., Liu, R

    Rustamkulov, Z., Sing, D. K., Liu, R. & Wang, A. Analysis of a JWST NIR- Spec Lab Time Series: Characterizing Systematics, Recovering Exoplanet Transit Spectroscopy, and Constraining a Noise Floor.Astrophys. J. Lett.928, L7 (2022)

    2022

  39. [39]

    Rustamkulov, Z.et al.Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM.Nature614, 659–663 (2023)

    2023

  40. [40]

    K.et al.A warm Neptune’s methane reveals core mass and vigorous atmospheric mixing.Nature630, 831–835 (2024)

    Sing, D. K.et al.A warm Neptune’s methane reveals core mass and vigorous atmospheric mixing.Nature630, 831–835 (2024)

    2024

  41. [41]

    Open Source Softw.7, 4503 (2022)

    Bell, T.et al.Eureka!: An End-to-End Pipeline for JWST Time-Series Observations.J. Open Source Softw.7, 4503 (2022)

    2022

  42. [42]

    & Sing, D

    Liu, R., Wang, L.-C., Rustamkulov, Z. & Sing, D. K. Unveiling the Atmosphere of the Super-Jupiter HAT-P-14 b with JWST NIRISS and NIRSpec.Astron. J. 169, 335 (2025)

    2025

  43. [43]

    Science392, 858–862 (2026)

    Mukherjee, S.et al.Cloudy mornings and clear evenings on a gas giant exoplanet. Science392, 858–862 (2026)

    2026

  44. [44]

    Wang, L.-C.et al.A Comprehensive Analysis of the Panchromatic Transmission Spectrum of the Hot-Saturn WASP-96 b: Nondetection of Haze, Possible Sodium Limb Asymmetry, Stellar Characterization, and Formation History.Astron. J. 171, 147 (2026)

    2026

  45. [45]

    Radica, M.et al.Awesome SOSS: transmission spectroscopy of WASP-96b with NIRISS/SOSS.Mon. Not. R. Astron. Soc.524, 835–856 (2023)

    2023

  46. [46]

    22 Astrophys

    Fu, G.et al.Water and an Escaping Helium Tail Detected in the Hazy and Methane-depleted Atmosphere of HAT-P-18b from JWST NIRISS/SOSS. 22 Astrophys. J. Lett.940, L35 (2022)

    2022

  47. [47]

    Bourrier, V.et al.Hot Exoplanet Atmospheres Resolved with Transit Spec- troscopy (HEARTS). III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121b.Astron. Astrophys.635, A205 (2020)

    2020

  48. [48]

    Newville, M., Stensitzki, T., Allen, D. B. & Ingargiola, A. LMFIT: Non-Linear Least-Square Minimization and Curve-Fitting for Python (2015). URL https: //doi.org/10.5281/zenodo.11813

    work page doi:10.5281/zenodo.11813 2015

  49. [49]

    W., Lang, D

    Foreman-Mackey, D., Hogg, D. W., Lang, D. & Goodman, J. emcee: The MCMC Hammer.Publ. Astron. Soc. Pac.125, 306 (2013)

    2013

  50. [50]

    Speagle, J. S. DYNESTY: a dynamic nested sampling package for estimating Bayesian posteriors and evidences.Mon. Not. R. Astron. Soc.493, 3132–3158 (2020)

    2020

  51. [51]

    & Wakeford, H

    Grant, D. & Wakeford, H. R. Exo-TiC/ExoTiC-LD: ExoTiC-LD v3.0.0. Zenodo (2022)

    2022

  52. [52]

    & Asplund, M

    Magic, Z., Chiavassa, A., Collet, R. & Asplund, M. The Stagger-grid: A grid of 3D stellar atmosphere models. IV. Limb darkening coefficients.Astron. Astrophys. 573, A90 (2015)

    2015

  53. [53]

    & Leconte, J

    Falco, A., Zingales, T., Pluriel, W. & Leconte, J. Toward a multidimensional analysis of transmission spectroscopy. I. Computation of transmission spectra using a 1D, 2D, or 3D atmosphere structure.Astron. Astrophys.658, A41 (2022)

    2022

  54. [54]

    URL https://www.sciencedirect.com/science/article/pii/ S0022285216300807

    Tennyson, J.et al.The exomol database: Molecular line lists for exo- planet and other hot atmospheres.Journal of Molecular Spectroscopy 327, 73–94 (2016). URL https://www.sciencedirect.com/science/article/pii/ S0022285216300807. New Visions of Spectroscopic Databases, Volume II

    2016

  55. [55]

    & Chabrier, G

    Leconte, J., Lai, D. & Chabrier, G. Distorted, nonspherical transiting planets: impact on the transit depth and on the radius determination.Astron. Astrophys. 528, A41 (2011)

    2011

  56. [56]

    L.et al.JWST COMPASS: A NIRSpec/G395H Transmission Spectrum of the Sub-Neptune TOI-836c.Astron

    Wallack, N. L.et al.JWST COMPASS: A NIRSpec/G395H Transmission Spectrum of the Sub-Neptune TOI-836c.Astron. J.168, 77 (2024)

    2024

  57. [57]

    J.169, 142 (2025)

    Alderson, L.et al.JWST COMPASS: NIRSpec/G395H Transmission Observa- tions of the Super-Earth TOI-776 b.Astron. J.169, 142 (2025)

    2025

  58. [58]

    V., Apai, D

    Rackham, B. V., Apai, D. & Giampapa, M. S. The Transit Light Source Effect: False Spectral Features and Incorrect Densities for M-dwarf Transiting Planets. Astrophys. J.853, 122 (2018). 23

    2018

  59. [59]

    Kostogryz, N.et al.The Effect of Stellar Magnetic Activity on Measurements of Morning and Evening Asymmetry of Planetary Terminator.Astrophys. J. Lett. 989, L6 (2025)

    2025

  60. [60]

    Delrez, L.et al.WASP-121 b: a hot Jupiter close to tidal disruption transiting an active F star.Mon. Not. R. Astron. Soc.458, 4025–4043 (2016)

    2016

  61. [61]

    V., Apai, D

    Rackham, B. V., Apai, D. & Giampapa, M. S. The Transit Light Source Effect. II. The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars.Astron. J.157, 96 (2019)

    2019

  62. [62]

    M.et al.An Optical Transmission Spectrum for the Ultra-hot Jupiter WASP-121b Measured with the Hubble Space Telescope.Astron

    Evans, T. M.et al.An Optical Transmission Spectrum for the Ultra-hot Jupiter WASP-121b Measured with the Hubble Space Telescope.Astron. J.156, 283 (2018)

    2018

  63. [63]

    The radiative equilibrium of a rotating system of gaseous masses

    von Zeipel, H. The radiative equilibrium of a rotating system of gaseous masses. Mon. Not. R. Astron. Soc.84, 665–683 (1924)

    1924

  64. [64]

    Barnes, J. W. Transit Lightcurves of Extrasolar Planets Orbiting Rapidly Rotating Stars.Astrophys. J.705, 683–692 (2009)

    2009

  65. [65]

    & Pope, B

    Dholakia, S., Dholakia, S. & Pope, B. J. S. A General, Differentiable Transit Model for Ellipsoidal Occulters: Derivation, Application, and Forecast of Plane- tary Oblateness and Obliquity Constraints with JWST.Astrophys. J.987, 150 (2025)

    2025

  66. [66]

    & Jankowiak, M

    Phan, D., Pradhan, N. & Jankowiak, M. Composable Effects for Flexi- ble and Accelerated Probabilistic Programming in NumPyro.arXiv e-prints arXiv:1912.11554 (2019)

    Pith/arXiv arXiv 1912

  67. [67]

    P.et al.Gravity-darkening Analysis of the Misaligned Hot Jupiter MASCARA-4 b.Astrophys

    Ahlers, J. P.et al.Gravity-darkening Analysis of the Misaligned Hot Jupiter MASCARA-4 b.Astrophys. J.888, 63 (2020)

    2020

  68. [68]

    Hoffman, M. D. & Gelman, A. The No-U-Turn Sampler: Adaptively Setting Path Lengths in Hamiltonian Monte Carlo.arXiv e-printsarXiv:1111.4246 (2011)

    Pith/arXiv arXiv 2011

  69. [69]

    D.et al.Imaging the Surface of Altair.Science317, 342 (2007)

    Monnier, J. D.et al.Imaging the Surface of Altair.Science317, 342 (2007)

    2007

  70. [70]

    JWST NIRSpec G395H phase curve of WASP-121b.MAST(2024)

    Sing, D. JWST NIRSpec G395H phase curve of WASP-121b.MAST(2024). URL https://doi.org/10.17909/6qnn-6j23

    work page doi:10.17909/6qnn-6j23 2024

  71. [71]

    WASP-121b JWST NIRISS/SOSS Phase Curve.MAST(2025)

    Splinter, J. WASP-121b JWST NIRISS/SOSS Phase Curve.MAST(2025). URL https://doi.org/10.17909/ppjp-9743

    work page doi:10.17909/ppjp-9743 2025

  72. [72]

    Astrophys.558, A33 (2013)

    Astropy Collaborationet al.Astropy: A community Python package for astronomy.Astron. Astrophys.558, A33 (2013). 24

    2013

  73. [73]

    J.156, 123 (2018)

    Astropy Collaborationet al.The Astropy Project: Building an Open-science Project and Status of the v2.0 Core Package.Astron. J.156, 123 (2018)

    2018

  74. [74]

    Astropy Collaborationet al.The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package.Astrophys. J. Lett.935, 167 (2022)

    2022

  75. [75]

    corner.py: Scatterplot matrices in python.J

    Foreman-Mackey, D. corner.py: Scatterplot matrices in python.J. Open Source Softw.1, 24 (2016). URL https://doi.org/10.21105/joss.00024

    work page doi:10.21105/joss.00024 2016

  76. [76]

    Hunter, J. D. Matplotlib: A 2D Graphics Environment.Comput. Sci. Eng.9, 90–95 (2007)

    2007

  77. [77]

    Harris and K

    Harris, C. R.et al.Array programming with numpy.Nature585, 357–362 (2020). URL https://doi.org/10.1038/s41586-020-2649-2

    work page doi:10.1038/s41586-020-2649-2 2020

  78. [78]

    Data structures for statistical computing in python (2010)

    McKinney, W. Data structures for statistical computing in python (2010)

    2010

  79. [79]

    Methods17, 261–272 (2020)

    Virtanen, P.et al.Scipy 1.0: fundamental algorithms for scientific computing in python.Nat. Methods17, 261–272 (2020). URL https://doi.org/10.1038/ s41592-019-0686-2. Extended Data Extended Data Table 1Metrics from the MCMC and nested samplings to the NIRISS SOSS first order white light curve. Data reduction Firefly Fu Model Mtra Mrot Mrot Mtra Mrot Mrot ...

    2020