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End-to-end simulations show RISTRETTO can detect Proxima b in reflected light in about 55 hours, and its O2 and H2O signatures in about 85 hours.

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End-to-end simulations forecast that RISTRETTO can detect Proxima b in reflected light in 55 hours and constrain its albedo to 20%, with molecular features emerging near 85 hours under an Earth-like atmosphere assumption.

T0 review reviewed 2026-08-04 challenge →

load-bearing objection A careful simulation that makes the 55-hour planet detection credible, but the abstract's 85-hour O2/H2O claim is a matched-filter upper bound, and H2O is not detected by the simpler molecular model even at 100 hours. the 4 major comments →

arxiv 2509.07644 v1 pith:NVKM6AJN submitted 2025-09-09 astro-ph.EP astro-ph.IM

Simulating RISTRETTO: Proxima b detectability in reflected light

Maddalena Bugatti , Christophe Lovis , Nicolas Billot , Nicolas Blind , Baptiste Lavie , Martin Turbet , Bruno Chazelas , Francesco Pepe This is my paper
classification astro-ph.EP astro-ph.IM
keywords reflected-light spectroscopyProxima bhigh-contrast imaginghigh-resolution spectroscopyexoplanet atmospheresalbedoadaptive opticsintegral-field spectrograph
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

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

The reading

This paper argues that RISTRETTO, a planned high-resolution integral-field spectrograph for ESO's VLT, can detect the temperate rocky planet Proxima b in reflected starlight in about 55 hours of observing time, assuming an Earth-like atmosphere. At that cost the planet's orbital inclination and planet-to-star flux ratio would be recovered to about 20 percent precision, giving the planet's true mass through the known minimum mass and a broadband albedo through mass-radius relations. With roughly 85 hours, the high-resolution albedo spectrum becomes statistically favored, meaning molecular absorption by oxygen and water is visible; a simple O2 model gives a clear detection at 100 hours while H2O needs more. The simulations are end-to-end: a 3D climate-model spectrum of Proxima b is Doppler-shifted and propagated through simulated extreme-adaptive-optics and coronagraphic coupling curves, then through a realistic echelle spectrograph with photon and read noise, tellurics, and spectral extraction. The paper also presents a two-hour technique that locates the stellar spin axis on the sky to about ±5.4 degrees, which for spin-orbit aligned systems fixes the planet's line of nodes and saves up to a factor of two in observing time. If these results hold, RISTRETTO would open the first reflected-light window onto a temperate rocky exoplanet atmosphere with an 8-meter-class telescope.

Core claim

The central claim is that RISTRETTO can detect Proxima b's reflected light at high significance in 55 hours (best 50 hours retained) when the planet has an Earth-like N2-O2 atmosphere with 400 ppm CO2 and a water-covered surface. The detection criterion is 20% precision on the planet-to-star flux ratio, a stricter requirement than simple detection; at this exposure the log-Bayes factor favoring a constant-albedo planet model over a no-planet model averages 10.5, and the recovered inclination and flux ratio match the simulated values aside from a systematic ~20% underestimate caused by setting the planet-position coupling ratio to unity in the model. With 80-85 hours the full simulated albedo

What carries the argument

The observable that carries the detection is the normalized long-to-short exposure ratio of each echelle order (one spectral strip of the cross-dispersed format), Eq. 8, which removes broadband telluric and instrumental transmission; in that ratio the planet appears as the stellar spectrum Doppler-shifted by the planet's orbital motion and scaled by the albedo, phase function, radius ratio, and the ratio of IFU coupling efficiencies. The load-bearing instrument quantity is the simulated coupling curve of the coronagraphic IFU: off-axis fibers suppress the stellar halo to a few × 10^-4 while retaining 30-50% coupling for the planet. The spin-axis technique exploits the steep radial gradient o

Load-bearing premise

The simulated XAO-plus-coronagraph coupling curves, especially off-axis stellar-halo suppression of about 1e-4 and 30-50% planet coupling, faithfully represent the real RISTRETTO front end; required exposure times scale roughly with the inverse square of the achieved planet-to-halo contrast.

What would settle it

Measure the actual off-axis stellar-halo coupling and planet coupling of the RISTRETTO front end on sky under median seeing (0.76 arcsec) and elevation 43 degrees: if the off-axis halo coupling is double the simulated few × 10^-4, the 55-hour forecast becomes roughly 220 hours. Alternatively, a first-light campaign that does not detect Proxima b at the predicted 20%-albedo precision after 100 hours, or detects it at a significantly different inclination or flux ratio, would rule out the simulated Earth-like scenario or the coupling model.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • 55 hours of RISTRETTO time would turn Proxima b from a radial-velocity signal into a measured inclination, true mass, and 20%-precision broadband albedo, breaking the Mp sin i degeneracy.
  • 85 hours would make the reflected spectrum informative enough to claim molecular absorption by O2 and H2O for an Earth-like planet, the first such measurement for a temperate rocky exoplanet.
  • The stellar spin-axis method constrains the ascending node to ±5.4 degrees, enabling a single IFU orientation and halving the needed exposure time for aligned systems; it also yields the stellar inclination through the RV semi-amplitude.
  • The restrictive observing constraints (seeing < 0.97 arcsec, airmass < 1.7) still leave about 241 usable hours in a season, so the 55-hour detection is schedulable in one year.
  • The same instrument can detect easier targets in a few hours to a few nights, so the methodology generalizes beyond Proxima b to a small sample of nearby gas giants, Neptunes, and super-Earths.

Where Pith is reading between the lines

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

  • If the real on-sky off-axis halo suppression is a factor of two worse than the simulated few × 10^-4 coupling, the 55-hour and 85-hour forecasts would roughly quadruple; the first engineering run should measure the coupling maps directly.
  • The normalized-ratio and differential-limb-coupling techniques are transferable to ELT-class instruments, so the paper effectively rehearses the observing and analysis scheme for reflected-light spectroscopy of Earth analogs at larger apertures.
  • The spin-orbit alignment assumption is testable: if the stellar spin axis and orbit are misaligned, the method would still measure the stellar inclination but would not fix the ascending node, and the 30-degree-rotated double-exposure strategy would remain necessary.
  • By fitting a phase function, the same data could probe orbital phase dependence; observations closer to superior conjunction trade increased reflected flux against smaller angular separation, and the paper's fixed 90-degree-phase assumption likely brackets what is achievable.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

4 major / 3 minor

Summary. The paper presents end-to-end simulations of the proposed RISTRETTO instrument observing Proxima b in reflected light. The authors generate synthetic stellar and planetary spectra, model AO/coronagraph/IFU coupling functions from prior work, propagate the spectra through the PyEchelle spectrograph simulator, and apply a Bayesian nested-sampling framework to a normalized long-exposure/short-exposure ratio. They fit five planet models of increasing complexity. The central quantitative claims are that Proxima b can be detected with a constant-albedo model in about 55 hours of observing time (50 usable hours), reaching ~20% precision on the planet-to-star flux ratio, and that molecular absorption by O2 and H2O can be detected in about 85 hours. A separate section develops a method to constrain the stellar spin-axis orientation using differential coupling in the central single-mode fiber.

Significance. If the 55-hour detection claim holds, this is a significant result: it quantifies a plausible path to the first reflected-light spectroscopy of a temperate rocky exoplanet with a VLT-class instrument, and it introduces a data-analysis methodology that is largely independent of the assumed planetary spectrum. The spin-axis orientation method (Sec. 6) is innovative and is tested over ten noise realizations with consistent recovery of the input angle. The authors are also transparent about several limitations, including the in-sample nature of the full-albedo fit and the omission of the third coupling-function ratio. However, the abstract's molecular-detection claim is not supported by the paper's own results, and the 85-hour figure is a matched-filter upper bound rather than a demonstrated detection of O2 and H2O.

major comments (4)
  1. [Abstract; Sec. 5.2.4; Sec. 7.1] The abstract states that 'molecular absorption by O2 and H2O can be detected in about 85 hours of observations.' This is internally inconsistent with Sec. 5.2.4, where the HITRAN-based molecular model gives Delta ln Z close to zero for H2O after 100 hours (Appendix C.2), and with Sec. 7.1, which says H2O 'could be detectable with exposure times exceeding 100 hours.' The 85-hour value in Fig. 19 is obtained from the full-albedo model, not from an O2/H2O-specific detection. Please remove the H2O claim from the abstract, or explicitly condition it on an a priori known albedo template.
  2. [Sec. 4.3.3; Sec. 5.2.3] The 'full albedo spectrum' model is an in-sample matched filter: it uses exactly the GCM/PICASO albedo spectrum injected into the synthetic observations, with only a global scaling and inclination free. The Delta ln Z > 5 at ~80-85 h (Fig. 19) therefore measures detectability of a perfectly known template, not a blind or physically motivated detection of molecular bands. This is acknowledged in Sec. 5.2.3, but it is load-bearing for the molecular claim in the abstract. I recommend relabeling the 85-h figure as a matched-filter upper bound and, if molecular detection is to be claimed, adding a proper retrieval or a prior over albedo templates (e.g., the GCM library suggested in Sec. 7.2).
  3. [Sec. 3.5; Sec. 5.1] The 55-h and 85-h forecasts scale approximately as the inverse square of the achieved planet-to-halo contrast, but the paper provides no sensitivity analysis on the IFU coupling functions from Blind et al. (2024). The off-axis stellar-halo suppression of order 1e-4 and the planet coupling efficiency of 30-50% (Sec. 3.5, Figs. 5 and 8) are load-bearing for both exposure-time claims. The text notes residual ADC errors and finite-simulation-time imbalances but does not quantify how the required exposure times would change under, say, a 2x degradation in halo suppression or a 20% lower planet coupling. A simple scaling table or a small grid of coupling-curve perturbations would substantially increase confidence in the headline numbers.
  4. [Sec. 4.3.1; Sec. 5.2.1] The 20% albedo 'precision' reported in Sec. 5.2.1 is statistical precision only. The same section states that the mean flux ratio is underestimated by ~20% because the third coupling-function ratio rho^p_i(r)/rho^s_i(r_off) is set to 1 in the model (Sec. 4.3.1). Thus the demonstrated capability is a 20%-wide posterior centered ~20% below the true value, which does not by itself establish 20%-accurate albedo characterization. Please provide a combined statistical+systematic error budget, or rephrase the claim as '20% statistical precision before calibration of the planet-position coupling ratio.'
minor comments (3)
  1. [Sec. 5.1] The sentence 'using the best 80 hours out of 75' appears to be a typo; presumably it should read 'best 75 out of 80' or similar. Please correct.
  2. [Sec. 4.2, Eq. (8)] The notation <F1/F2>_o is used before the weighted average is defined in the preceding paragraph; consider adding a brief definition at the point of first use to help the reader.
  3. [Sec. 2.1.1] The statement that the IFU projects 'approximately 37 milliarcseconds between the centers of adjacent spaxels' is ambiguous: it would be clearer to specify the spaxel pitch and the lenslet size separately, since the coupling maps in Fig. 8 are plotted in milliarcseconds.

Circularity Check

1 steps flagged

The 55-h planet detection is an independent injection-recovery result, but the 85-h O2/H2O molecular detection is an in-sample matched filter: the 'full albedo spectrum' model is the exact spectrum used to generate the synthetic data, so the molecular detection is built in by construction.

specific steps
  1. fitted input called prediction [Abstract; Sect. 4.3.3 'Full albedo spectrum'; Sect. 5.2.3 and Fig. 19; Sect. 7.1]
    "we only consider the exact same albedo spectrum that was used to generate the simulated spectra ... The actual parameter space of the model has been reduced to two dimensions because we have access to the 'true' planetary albedo spectrum (i.e., the one we used to build our synthetic observations)."

    The full albedo model is given the identical molecular absorption spectrum that was used to generate the simulated observations, with only a global scaling and inclination left free. The 80-85 h 'molecular signatures distinguishable' claim (Fig. 19) therefore measures the evidence for the injected template, not an independent detection of O2 or H2O. Because the model and the data generator share the same molecular absorption features, the Bayes-factor growth is forced by construction. The abstract's statement that 'molecular absorption by O2 and H2O can be detected in about 85 hours' is an in-sample matched-filter result. This is confirmed by Sec. 5.2.4, where the independent single-layer HITRAN model detects O2 at 100 h but yields 'close to zero' preference for H2O, contradicting the abst

full rationale

The paper's central 55-h detection claim is not circular: it is obtained with a constant-albedo model (Eq. 10) that does not use the injected spectrum's molecular structure, and it is validated against the no-planet model with a Bayes-factor threshold plus a 20% albedo-precision criterion. The orbital inclination recovery and the spin-axis constraint method are also independent, self-contained simulations. However, the second headline result—85 h for O2 and H2O molecular detection—does reduce by construction. The 'full albedo spectrum' model in Sect. 4.3.3 explicitly adopts the exact GCM/PICASO spectrum used to make the synthetic data, with only a free scaling. Consequently, the 80-85 h molecular detection in Fig. 19 is a matched filter on the truth, not a blind or physically motivated molecular detection. The paper is transparent about this in Sects. 5.2.3 and 7.1, but the abstract overstates it, and the independent HITRAN molecular model in Sec. 5.2.4 finds no H2O preference even at 100 h, making the abstract's H2O claim internally inconsistent. Other cited inputs, notably the IFU coupling functions from Blind et al. (2024), are external end-to-end instrument simulations and do not constitute circularity. Overall: one central sub-claim reduces to its input by construction, while the primary planet-detection claim remains independent, giving partial circularity.

Axiom & Free-Parameter Ledger

9 free parameters · 8 axioms · 0 invented entities

The forecast rests on synthetic inputs (PHOENIX star, GCM/PICASO planet) and simulated XAO/coronagraph coupling functions that are not independently verified on sky. The full-albedo molecular sensitivity uses the injected spectrum as the model, and the planet coupling ratio is set to 1 rather than its simulated value of about 0.86. Free parameters p, i, N, P, scaling, and coupling assumptions are listed above.

free parameters (9)
  • Planet-to-star flux ratio p (constant albedo model) = p = 0.83 +/- 0.16 x 1e-7 for the 55-hour example; true injected value about 1e-7, with mean underestimated by about 20%
    Fitted to simulated normalized ratios (Eq. 10); it is the target parameter for albedo determination.
  • Orbital inclination i = 60.39 +/- 1.27 deg in example posterior; true value 60 deg
    Free parameter in constant, chromatic, full, and molecular models; sets the planet radial velocities.
  • Chromatic albedo bin values p_1..p_n = n = 2, 3, 5, 10 bins over 620-840 nm; 5-parameter fit shown in Fig. 18
    Piecewise planet flux ratio model (Eq. 11) with n+1 free parameters.
  • Full albedo scaling factor = Not quoted separately; multiplicative factor on the injected GCM/PICASO albedo spectrum
    Only fitted parameter with inclination in the full albedo model; the spectrum itself is taken from the simulated truth.
  • Molecular column density N = O2 model: N = 7.62 +1.70/-3.09 x 1e26 mol/cm2; H2O model: N = 3.58 +6.64/-2.54 x 1e21 mol/cm2
    Free parameter in the single-layer molecular absorption model (Eqs. 12-13); posterior is broad and poorly constrained.
  • Molecular pressure P = O2 P = 2.38 +0.90/-0.67 bar; H2O P = 0.84 +0.74/-0.64 bar; temperature fixed at 250 K
    Free parameter in the molecular model; temperature was held fixed for simplicity.
  • Third coupling function ratio rho_p_i(r)/rho_s_i(roff) = Assumed 1.0; true simulation value about 0.86
    Not fitted but set to unity in the modeling (Sect. 4.3.1); induces the acknowledged 20% underestimation of the flux ratio in Sect. 5.2.1.
  • Spin-axis sine amplitude A = A = 2.21 +/- 0.10 m/s for one MCMC example
    Fitted together with theta_s in the spin-axis orientation method (Eq. 17); depends on stellar v sin i and the coupling curve.
  • Stellar spin axis orientation theta_s = Recovered within +/-5.4 deg of true value 0 across 10 simulations
    Free parameter in the spin-axis method.
axioms (8)
  • domain assumption Proxima b orbital elements from Mascareno et al. (2025) are correct, with eccentricity fixed to 0.
    Used to build the sky orbit and radial velocities in Sect. 3.2 and Table 1.
  • domain assumption The PHOENIX synthetic spectrum accurately represents Proxima's stellar spectrum; stellar activity and flares are neglected.
    The stellar template and reflected-light contrast are built on this spectrum in Sect. 3.1.
  • domain assumption The GCM/PICASO Earth-like atmosphere (1 bar N2-O2, 400 ppm CO2, water surface, self-consistent clouds) produces a realistic reflected planet spectrum.
    The injected planet spectrum is generated from this model in Sect. 3.1; all detectability numbers assume this atmosphere.
  • domain assumption The RISTRETTO AO plus coronagraph coupling functions from Blind et al. (2024) predict on-sky performance.
    All halo suppression and planet coupling efficiencies come from these simulations in Sect. 3.5.
  • domain assumption The stellar spin axis is aligned with the Proxima b orbital plane (small obliquity).
    The spin-axis method constrains the longitude of the ascending node only for aligned systems, stated in Sect. 6 and the abstract.
  • domain assumption The planet reflected spectrum is fixed at a 90-degree orbital phase angle for all epochs; phase function variations are ignored.
    Stated in Sect. 3.1 and listed as a future improvement in Sect. 7.2.
  • ad hoc to paper The full albedo model uses exactly the injected albedo spectrum, without exploring the true GCM parameter space.
    Sect. 4.3.3 and Sect. 5.2.3 acknowledge that this is a two-parameter reduction to the known truth, not a retrieval.
  • ad hoc to paper The best 90-95% of exposures are selected a posteriori, and the 55-hour estimate uses the best 50 of 55 one-hour exposures.
    Sect. 5.1 and Sect. 5.2.1 describe this selection; its effect on the quoted exposure times is not separately quantified.

reviewed 2026-08-04 · how reviews work

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Cite this review

Pith. "Pith review of Simulating RISTRETTO: Proxima b detectability in reflected light." pith.science (2026). https://pith.science/paper/NVKM6AJN

@misc{pith2026250907644,
  author       = {Pith},
  title        = {Pith review of: Simulating RISTRETTO: Proxima b detectability in reflected light},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/NVKM6AJN}},
  note         = {Machine review of arXiv:2509.07644}
}
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abstract

The characterization of exoplanet atmospheres is one of the key topics in modern astrophysics. To date, transmission spectroscopy has been the primary method used, but upcoming instruments will lay the foundation for advancing reflected-light spectroscopy. The main challenge in this area of research is the high contrast ratio between the planet and its star. RISTRETTO, a high-resolution integral-field spectrograph designed for ESO's VLT, aims to address these limitations through a combination of extreme AO, coronagraphy, and high-resolution spectroscopy. The goal of this paper is to demonstrate the detectability of the temperate rocky planet Proxima b with RISTRETTO, using realistic end-to-end simulations and a specifically developed data analysis methodology. We created high-resolution star and planet spectra, selecting realistic observational epochs and incorporating the predicted performance of the AO and coronagraphic systems. We implemented noise and spectrograph effects through the Pyechelle spectrograph simulator. We then applied a new methodology to isolate the signal of the planet from the stellar one and proceeded to fit several planetary models in order of increasing complexity. We also introduced a method to determine the sky orientation of the stellar spin axis, which constrains the orientation of the planetary orbit for aligned systems. Assuming an Earth-like atmosphere, our results show that RISTRETTO can detect Proxima b in reflected light in about 55 hours of observing time, offering the ability to characterize the planet orbital inclination, true mass, and broadband albedo. In addition, molecular absorption by O$_2$ and H$_2$O can be detected in about 85 hours of observations. These findings highlight the potential of RISTRETTO to significantly advance the field of exoplanetary science by enabling reflected-light spectroscopy of a sample of nearby exoplanets.

Figures

Figures reproduced from arXiv: 2509.07644 by Baptiste Lavie, Bruno Chazelas, Christophe Lovis, Francesco Pepe, Maddalena Bugatti, Martin Turbet, Nicolas Billot, Nicolas Blind.

Figure 1
Figure 1. Figure 1: RISTRETTO diagram. 2.1.1. XAO front-end and coronagraphic IFU The front-end design and performance are addressed in detail in Blind et al. (2024) and Blind et al. (2025). For our purposes, we summarize the front-end output as a set of IFU coupling curves, the derivation of which is described in Blind et al. (2024). The RISTRETTO IFU features seven hexagonal lenslets (spaxels); namely, a central one surroun… view at source ↗
Figure 2
Figure 2. Figure 2: Left panel: RISTRETTO long exposure with the IFU [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Upper plot: Albedo spectrum Fp/Fs of Proxima b for an Earth-like atmosphere. Lower plot: Normalized planetary (Fp) and stellar (Fs) spectra. Fp is generated at an orbital phase of 90°. All spectra have a resolution of ∼ 500, 000. plane (Hatzes 2016) remain unknown. Knowing these parame￾ters is essential for accurately determining the orbit of the exo￾planet in the plane of the sky as observed from Earth. P… view at source ↗
Figure 4
Figure 4. Figure 4: Proxima b’s possible trajectories as seen from Earth with [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Left panel: IFU transmission map into the 7 fibers for [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Airmass and elevation of Proxima Centauri during the [PITH_FULL_IMAGE:figures/full_fig_p005_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Orbital radial velocity of star and planet and separation [PITH_FULL_IMAGE:figures/full_fig_p006_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Top plot: IFU coupling functions for the 7 fibers, when [PITH_FULL_IMAGE:figures/full_fig_p006_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Pyechelle workflow: the spectrograph optics are modeled [PITH_FULL_IMAGE:figures/full_fig_p007_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Simulated 2D raw frame using PyEchelle and the [PITH_FULL_IMAGE:figures/full_fig_p007_10.png] view at source ↗
Figure 11
Figure 11. Figure 11: Creation of the stellar model spectrum (brown) from [PITH_FULL_IMAGE:figures/full_fig_p010_11.png] view at source ↗
Figure 12
Figure 12. Figure 12: Single-layer absorption spectra from molecular oxygen [PITH_FULL_IMAGE:figures/full_fig_p010_12.png] view at source ↗
Figure 13
Figure 13. Figure 13: Effective seeing (at elevation 45°) and elevation distri￾butions for Proxima Centauri at Paranal Observatory, Chile. We considered possible combinations of five elevations (38°, 43°, 48°, 52°, and 90°, with 90° serving as a reference) and five seeing conditions (0.52, 0.62, 0.76, 0.97, and 1.26 arcseconds, corresponding to the 10th, 25th, 50th, 75th, and 90th percentiles of the Paranal seeing distribution… view at source ↗
Figure 14
Figure 14. Figure 14: Average off-axis coupling functions, when an object is placed in the central spaxel, for different elevation and seeing conditions. We then computed the wavelength-averaged value of the ra￾tio ρ p i (r)/ p ρ s i (ron), which is proportional to the expected S/N on the planet spectrum in the photon-limited regime (Lovis et al. 2017). We found that observations with a seeing at zenith of 1.26 arcsec yield an… view at source ↗
Figure 15
Figure 15. Figure 15: ∆ ln Z between the model with constant albedo and the model without the planet as a function of exposure time. The solid line represents the mean across the 10 simulated datasets, while the shaded region indicates the corresponding scatter. p = 0.83 +0.16 0.16 [10 7 ] Median 1 2 3 0.5 1.0 1.5 p [10 7 ] 56 58 60 62 64 66 Inclination (deg) 55 60 65 Inclination (deg)= 60.39 +1.25 1.27 [PITH_FULL_IMAGE:figur… view at source ↗
Figure 16
Figure 16. Figure 16: Example of the posterior distributions for the orbital in [PITH_FULL_IMAGE:figures/full_fig_p012_16.png] view at source ↗
Figure 17
Figure 17. Figure 17: Posterior distributions (approximated by Gaussian func [PITH_FULL_IMAGE:figures/full_fig_p013_17.png] view at source ↗
Figure 19
Figure 19. Figure 19: ∆ ln Z between the full albedo model and the constant albedo model as a function of exposure time. The solid line rep￾resents the mean across the ten simulated datasets, while the shaded region indicates the corresponding scatter. In Fig.19, we show that the molecular signatures in the plane￾tary spectrum become distinguishable (∆ ln Z > 5) after approx￾imately 80–85 hours of exposure time. This confirms … view at source ↗
Figure 20
Figure 20. Figure 20: Coupling map of the central RISTRETTO fiber and a [PITH_FULL_IMAGE:figures/full_fig_p014_20.png] view at source ↗
Figure 22
Figure 22. Figure 22: Measured radial velocity differences between opposite exposures as a function of the position angle of the star within the central spaxel of RISTRETTO. The star is placed at a constant distance of 9 mas from the center. where j represents the j th pixel in a given order, F0 represents a reference high-S/N spectrum constructed by summing all 32 exposures, and Fa and Fb are spectra of opposite exposures. Fi… view at source ↗
Figure 21
Figure 21. Figure 21: Left panel: Radial velocity map on the surface of Prox [PITH_FULL_IMAGE:figures/full_fig_p015_21.png] view at source ↗
Figure 23
Figure 23. Figure 23: Estimated θs from the MCMC posteriors for 10 different simulations. Each value represents the median of the posterior, and the errors are computed as the 16th and 84th percentiles. The horizontal line shows the true θs value used in the simulation. The shaded region illustrates an angular range of ±5.4 ◦ , which corresponds to a tangential offset of 3.5 mas at 2 λ/D for the RISTRETTO IFU. All calculated v… view at source ↗

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Works this paper leans on

74 extracted references · 58 canonical work pages · cited by 1 Pith paper

  1. [1]

    2024, A&A, 689, A245 Anglada-Escudé, G., Amado, P

    Alei, E., Quanz, S., Konrad, B., et al. 2024, A&A, 689, A245 Anglada-Escudé, G., Amado, P. J., Barnes, J., et al. 2016, nature, 536, 437

    work page 2024

  2. [2]

    D., Ruane, G., Jovanovic, N., et al

    Baker, A. D., Ruane, G., Jovanovic, N., et al. 2024, in Ground-based and Air- borne Instrumentation for Astronomy X, V ol. 13096, SPIE, 130961G

    work page 2024

  3. [3]

    E., Marley, M

    Batalha, N. E., Marley, M. S., Lewis, N. K., & Fortney, J. J. 2019, ApJ, 878, 70

    work page 2019

  4. [4]

    Chazelas, B., et al

    Blind, N., Restori, N., . Chazelas, B., et al. 2025, arXiv e-prints, arXiv:2503.18538

    work page arXiv 2025

  5. [5]

    2024, in Adaptive Optics Systems IX, V ol

    Blind, N., Shinde, M., Dinis, I., et al. 2024, in Adaptive Optics Systems IX, V ol. 13097, SPIE, 1622–1634

    work page 2024

  6. [6]

    2013, A&A, 549, A109

    Bonfils, X., Delfosse, X., Udry, S., et al. 2013, A&A, 549, A109

    work page 2013

  7. [7]

    J., Koch, D., Basri, G., et al

    Borucki, W. J., Koch, D., Basri, G., et al. 2010, Science, 327, 977

    2010

  8. [8]

    2001, A&A, 374, 733

    Bouchy, F., Pepe, F., & Queloz, D. 2001, A&A, 374, 733

    work page 2001

  9. [9]

    2024, A&A, 691, A113

    Bourrier, V ., Delisle, J.-B., Lovis, C., et al. 2024, A&A, 691, A113

    work page 2024

  10. [10]

    S., V on Braun, K., Van Belle, G., et al

    Boyajian, T. S., V on Braun, K., Van Belle, G., et al. 2012, ApJ, 757, 112

    work page 2012

  11. [11]

    2016, Statistics and Computing, 26, 383

    Buchner, J. 2016, Statistics and Computing, 26, 383

    2016

  12. [12]

    2019, PASP, 131, 108005

    Buchner, J. 2019, PASP, 131, 108005

    2019

  13. [13]

    2021, The Journal of Open Source Software, 6, 3001

    Buchner, J. 2021, The Journal of Open Source Software, 6, 3001

    2021

  14. [14]

    J., et al

    Cadieux, C., Doyon, R., MacDonald, R. J., et al. 2024, ApJL, 970, L2

    2024

  15. [15]

    2024, in Ground-based and Airborne Instrumentation for Astronomy X, V ol

    Chazelas, B., Lovis, C., Blind, N., et al. 2024, in Ground-based and Airborne Instrumentation for Astronomy X, V ol. 13096, SPIE, 2201–2209

    work page 2024

  16. [16]

    Currie, M. H. & Meadows, V . S. 2025, , 6, 96

    work page 2025

  17. [17]

    Damiano, M. & Hu, R. 2021, AJ, 162, 200

    work page 2021

  18. [18]

    Dressing, C. D. & Charbonneau, D. 2013, ApJ, 767, 95

    work page 2013

  19. [19]

    2023 European Southern Observatory

    Ducrot, E., Lagage, P.-O., Min, M., et al. 2023 European Southern Observatory. 2024

    work page 2023

  20. [20]

    & Sajadian, S

    Fatheddin, H. & Sajadian, S. 2024, AJ, 168, 71

    work page 2024

  21. [21]

    2024, in Space Telescopes and Instru- mentation 2024: Optical, Infrared, and Millimeter Wave, V ol

    Feinberg, L., Ziemer, J., Ansdell, M., et al. 2024, in Space Telescopes and Instru- mentation 2024: Optical, Infrared, and Millimeter Wave, V ol. 13092, SPIE, 511–522

    work page 2024

  22. [22]

    L., Blank, D

    Feliz, D. L., Blank, D. L., Collins, K. A., et al. 2019, AJ, 157, 226

    work page 2019

  23. [23]

    Fischer, D. A. 2021, in ExoFrontiers: Big questions in exoplanetary science (IOP Publishing Bristol, UK), 4–1

    work page 2021

  24. [24]

    W., Lang, D., & Goodman, J

    Foreman-Mackey, D., Hogg, D. W., Lang, D., & Goodman, J. 2013, PASP, 125, 306

    2013

  25. [25]

    D., Hogg, D

    Foreman-Mackey, D., Morton, T. D., Hogg, D. W., Agol, E., & Schölkopf, B. 2016, AJ, 152, 206 Gaia Collaboration, Brown, A. G. A., Vallenari, A., et al. 2021, A&A, 649, A1

    work page 2016

  26. [26]

    2016, MNRAS, 457, 2877

    Gaidos, E., Mann, A., Kraus, A., & Ireland, M. 2016, MNRAS, 457, 2877

    work page 2016

  27. [27]

    T., Robinson, T

    Gialluca, M. T., Robinson, T. D., Rugheimer, S., & Wunderlich, F. 2021, PASP, 133, 054401

    work page 2021

  28. [28]

    E., Rothman, L

    Gordon, I. E., Rothman, L. S., Hargreaves, e. R., et al. 2022, Journal of quanti- tative spectroscopy and radiative transfer, 277, 107949

    work page 2022

  29. [29]

    2024, in Adaptive Optics Systems

    Guyon, O., Vievard, S., Lallement, M., et al. 2024, in Adaptive Optics Systems

    work page 2024

  30. [30]

    Hatzes, A. P. 2016, Methods of Detecting Exoplanets: 1st Advanced School on Exoplanetary Science, 3

    work page 2016

  31. [31]

    2018, A&A, 610, A47

    Hoeijmakers, H., Snellen, I., & Van Terwisga, S. 2018, A&A, 610, A47

    work page 2018

  32. [32]

    Horak, H. G. 1950, PhD thesis, The University of Chicago

    work page 1950

  33. [33]

    2013, A&A, 553, A6

    Husser, T.-O., Wende-von Berg, S., Dreizler, S., et al. 2013, A&A, 553, A6

    2013

  34. [34]

    P., & Dannert, F

    Kammerer, J., Quanz, S. P., & Dannert, F. 2022, A&A, 668, A52

    work page 2022

  35. [35]

    & Wright, J

    Kanodia, S. & Wright, J. 2018, RNAAS, 2, 4

    work page 2018

  36. [36]

    2021, The Messenger, 182, 38

    Kasper, M., Cerpa Urra, N., Pathak, P., et al. 2021, The Messenger, 182, 38

    work page 2021

  37. [37]

    V ., Gordon, I., Rothman, L., et al

    Kochanov, R. V ., Gordon, I., Rothman, L., et al. 2016, Journal of Quantitative Spectroscopy and Radiative Transfer, 177, 15

    work page 2016

  38. [38]

    2024, A&A, 682, A48

    Landman, R., Stolker, T., Snellen, I., et al. 2024, A&A, 682, A48

    work page 2024

  39. [39]

    E., Moore, A

    Larkin, J. E., Moore, A. M., Wright, S. A., et al. 2016, in Ground-based and Airborne Instrumentation for Astronomy VI, V ol. 9908, SPIE, 582–594 Lecavelier Des Etangs, A., Pont, F., Vidal-Madjar, A., & Sing, D. 2008, A&A, 481, L83

    work page 2016

  40. [40]

    2016, A&A, 587, A67

    Lendl, M., Delrez, L., Gillon, M., et al. 2016, A&A, 587, A67

    work page 2016

  41. [41]

    K., Showman, A

    Lewis, N. K., Showman, A. P., Fortney, J. J., Knutson, H. A., & Marley, M. S. 2014, ApJ, 795, 150

    work page 2014

  42. [42]

    2023, ApJL, 955, L22

    Lim, O., Benneke, B., Doyon, R., et al. 2023, ApJL, 955, L22

    2023

  43. [43]

    2024, in Ground-based and Airborne Instrumentation for Astronomy X, V ol

    Lovis, C., Blind, N., Chazelas, B., et al. 2024, in Ground-based and Airborne Instrumentation for Astronomy X, V ol. 13096, SPIE, 412–417

    work page 2024

  44. [44]

    2017, A&A, 599, A16

    Lovis, C., Snellen, I., Mouillet, D., et al. 2017, A&A, 599, A16

    work page 2017

  45. [45]

    2019, ARA&A, 57, 617

    Madhusudhan, N. 2019, ARA&A, 57, 617

    work page 2019

  46. [46]

    W., Feiden, G

    Mann, A. W., Feiden, G. A., Gaidos, E., Boyajian, T., & V on Braun, K. 2015, ApJ, 804, 64

    work page 2015

  47. [47]

    2022, in Ground-based and Air- borne Instrumentation for Astronomy IX, V ol

    Marconi, A., Abreu, M., Adibekyan, V ., et al. 2022, in Ground-based and Air- borne Instrumentation for Astronomy IX, V ol. 12184, SPIE, 720–735

    work page 2022

  48. [48]

    2015, A&A, 576, A134 Mascareño, A

    Martins, J., Santos, N., Figueira, P., et al. 2015, A&A, 576, A134 Mascareño, A. S., Faria, J., Figueira, P., et al. 2020, A&A, 639, A77 Mascareño, A. S. et al. 2025, A&A, accepted for publication

    work page 2015

  49. [49]

    & Queloz, D

    Mayor, M. & Queloz, D. 1995, Nature, 378, 355

    1995

  50. [50]

    D., Pascucci, I., & Apai, D

    Mulders, G. D., Pascucci, I., & Apai, D. 2015, ApJ, 814, 130

    work page 2015

  51. [51]

    2012, A&A, 543, A92

    Noll, S., Kausch, W., Barden, M., et al. 2012, A&A, 543, A92

    2012

  52. [52]

    2018, in Ground-based and Airborne Instrumentation for Astronomy VII, V ol

    Packham, C., Honda, M., Chun, M., et al. 2018, in Ground-based and Airborne Instrumentation for Astronomy VII, V ol. 10702, SPIE, 3118–3129

    work page 2018

  53. [53]

    2025, Experimental Astronomy, 59, 1

    Palle, E., Biazzo, K., Bolmont, E., et al. 2025, Experimental Astronomy, 59, 1

    work page 2025

  54. [54]

    2024, A&A, 688, A59

    Parc, L., Bouchy, F., Venturini, J., Dorn, C., & Helled, R. 2024, A&A, 688, A59

    work page 2024

  55. [55]

    2021, in ExoFrontiers: Big questions in exoplanetary science (IOP Publishing Bristol, UK), 3–1

    Pollacco, D., Batalha, N., Deleuil, M., & Ricker, G. 2021, in ExoFrontiers: Big questions in exoplanetary science (IOP Publishing Bristol, UK), 3–1

    work page 2021

  56. [56]

    V ., Apai, D., & Giampapa, M

    Rackham, B. V ., Apai, D., & Giampapa, M. S. 2018, ApJ, 853, 122

    2018

  57. [57]

    2024, in Advances in Optical and Mechan- ical Technologies for Telescopes and Instrumentation VI, V ol

    Restori, N., Blind, N., Kühn, J., et al. 2024, in Advances in Optical and Mechan- ical Technologies for Telescopes and Instrumentation VI, V ol. 13100, SPIE, 853–863

    work page 2024

  58. [58]

    D., Boyajian, T

    Ribas, I., Gregg, M. D., Boyajian, T. S., & Bolmont, E. 2017, A&A, 603, A58

    work page 2017

  59. [59]

    1981, in Progress in optics, V ol

    Roddier, F. 1981, in Progress in optics, V ol. 19 (Elsevier), 281–376

    work page 1981

  60. [60]

    M., et al

    Ruffio, J.-B., Macintosh, B., Konopacky, Q. M., et al. 2019, AJ, 158, 200

    2019

  61. [61]

    & Sasselov, D

    Seager, S. & Sasselov, D. D. 2000, ApJ, 537, 916

    2000

  62. [62]

    2011, A&A, 532, A1

    Selsis, F., Wordsworth, R., & Forget, F. 2011, A&A, 532, A1

    work page 2011

  63. [63]

    2006, Bayesian Analysis, 1

    Skilling, J. 2006, Bayesian Analysis, 1

    2006

  64. [64]

    2008, A&A, 487, 357

    Snellen, I., Albrecht, S., De Mooij, E., & Le Poole, R. 2008, A&A, 487, 357

    work page 2008

  65. [65]

    2015, A&A, 576, A59

    Snellen, I., de Kok, R., Birkby, J., et al. 2015, A&A, 576, A59

    work page 2015

  66. [66]

    Snellen, I. A. 2025, ARA&A, 63

    work page 2025

  67. [67]

    Sparks, W. B. & Ford, H. C. 2002, ApJ, 578, 543 Stürmer, J., Seifahrt, A., Robertson, Z., Schwab, C., & Bean, J. L. 2018, PASP, 131, 024502

    work page 2002

  68. [68]

    2008, Contemporary Physics, 49, 71

    Trotta, R. 2008, Contemporary Physics, 49, 71

    2008

  69. [69]

    2016, A&A, 596, A112

    Turbet, M., Leconte, J., Selsis, F., et al. 2016, A&A, 596, A112

    work page 2016

  70. [70]

    R., Birkby, J

    Vaughan, S. R., Birkby, J. L., Thatte, N., et al. 2024, MNRAS, 528, 3509

    work page 2024

  71. [71]

    2017, AJ, 153, 183

    Wang, J., Mawet, D., Ruane, G., Hu, R., & Benneke, B. 2017, AJ, 153, 183

    work page 2017

  72. [72]

    Winn, J. N. & Fabrycky, D. C. 2015, ARA&A, 53, 409

    2015

  73. [73]

    2023, ZEMAX Optical Design Software, accessed on December 18, 2023

    Zemax, LLC. 2023, ZEMAX Optical Design Software, accessed on December 18, 2023

    work page 2023

  74. [74]

    2023, Nature, 620, 746 Article number, page 17 of 18 A&A proofs: manuscript no

    Zieba, S., Kreidberg, L., Ducrot, E., et al. 2023, Nature, 620, 746 Article number, page 17 of 18 A&A proofs: manuscript no. output Appendix A: Barycentric radial velocities during the observational epochs Feb Mar Apr May Jun Jul 15 10 5 0 5 10 15 20 Barycentric RV (km/s) Fig. A.1: Barycentric correction during the observational epochs Appendix B: Star sp...

    work page 2023

This paper was first reviewed by deepseek-v4-flash on August 4, 2026.