{"id":"2b44fd8e-d60e-4056-a9ca-042785019220","arxiv_id":"2412.04171","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":4.0,"correctness_risk":"low","formal_verification":"none","parameter_count":3,"one_line_summary":"High-contrast imaging combined with Gaia astrometry constrains the unseen companions of HIP 11696 and HIP 47110 to planetary masses at 2.5-30 au and reveals candidate companions around HIP 36277.","lead":"Using two cameras on the Large Binocular Telescope, the authors imaged three nearby stars that show signs of an unseen companion from Gaia astrometry. They place tight limits on the mass and orbit of the likely planets and report one candidate companion that still needs confirmation.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"PMa-to-mass conversion (Eq. 1) assumes a single companion on a circular orbit; eccentric orbits or multiple companions could shift the quoted 4-16 MJup and 2.5-28 au ranges, and the paper offers no sensitivity test.","rationale":"The reader's weakest_assumption identifies exactly the same load-bearing concern: the conversion of the PMa signal to a companion mass assumes a single circular orbit, and the paper does not test the sensitivity to eccentricity or multiplicity. I agree with that assessment. The paper is a well-constructed constraints paper that appropriately flags the circular-orbit assumption in Section 4.2, but it does not quantify how the quoted ranges would change under more general orbital configurations. The central claim is an inference from a non-detection plus an astrometric signal, so the robustness of the PMa-to-mass relation is critical. The proposed Monte Carlo test would directly settle whether the assumption matters: if the mass-separation ranges are stable, the paper's numbers stand; if not, the authors would need to broaden the ranges or add a caveat. Either way, the scientific core—the DI limits and the use of SHARK-NIR—remains valid, so the CONDITIONAL verdict (pending the sensitivity test and the listed data/confirmation issues) is appropriate. No change to the reader's verdict is needed; hence verdict_should_be is UNCHANGED. I am not raising a new objection beyond what the reader already identified, but I am confirming it as the most load-bearing concern and proposing a concrete way to resolve it.","tokens_in":17699,"tokens_out":7730,"duration_ms":82173,"concrete_test":"Run a Monte Carlo sensitivity analysis for HIP 11696 and HIP 47110: draw eccentricities uniformly in [0, 0.9], random orientations and phases, and for each separation compute the companion mass required to reproduce the observed PMa vector (amplitude and direction) at the Gaia eDR3 epoch, while keeping the DI contrast limits and RUWE limits fixed. Then compare the 16th-84th percentile mass range at separations within the quoted bands (2.5-28 au and 3-30 au) to the abstract's mass bounds. If the spread exceeds ~20% of the quoted ranges, the circular-orbit single-companion assumption is load-bearing and the claims should be rephrased as conditional on that assumption.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim for HIP 11696 and HIP 47110 rests on Eq. 1 (from Kervella et al. 2019), which converts the measured PMa amplitude into a companion mass as a function of separation under the assumptions of a single companion on a circular orbit. Section 4.2 acknowledges the circular-orbit assumption and states the masses should be considered minimum values, but this is not a strict lower bound: for an eccentric orbit, the observed PMa depends on orbital phase, so a given mass can produce a larger or smaller PMa than a circular orbit at the same semi-major axis. Consequently, the quoted mass range (4-16 MJup for HIP 11696; ~3-10 MJup for HIP 47110) and the upper separation limits (28 au and 30 au), which are set where the PMa-required mass crosses the DI detection limit, could shift substantially if eccentricity is unconstrained. Likewise, if the PMa vector is the superposition of two or more companions rather than a single body, each individual companion could be less massive than inferred, making the phrase 'the companion responsible' ambiguous. The paper presents no test of these sensitivities, even as the abstract reports the resulting ranges as definitive estimates. This is the weakest load-bearing link because the DI and RUWE limits provide independent anchors, but the PMa curve is the only piece that ties the companion to the anomaly; moving it moves the intersection points that define the headline numbers.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper presents simultaneous high-contrast imaging with SHARK-NIR (H band) and LMIRCam (L' band) at LBT of three nearby stars with significant proper-motion anomalies (PMa) from Kervella et al. (2022). For HIP 11696 and HIP 47110, the authors combine PMa mass–separation estimates (Eq. 1, from Kervella et al. 2019), RUWE-based inner limits, and DI mass limits to constrain the putative companions to 2.5–28 au (4–16 MJup) and 3–30 au (~3–10 MJup), respectively. For HIP 36277, they detect a bound stellar/substellar companion at 1.95\" and a faint inner candidate at 0.625\"; the age ambiguity makes the interpretation dependent on whether 41 Myr or ~5 Gyr is assumed. The paper also validates the non-association of a previously known background source around HIP 11696 and demonstrates the synergy of simultaneous dual-band imaging.","tokens_in":18033,"tokens_out":8988,"duration_ms":91883,"significance":"If the constraints hold, the paper provides a useful demonstration of using PMa catalogs to prioritize direct-imaging follow-up and showcases SHARK-NIR's contrast performance. The analysis is well documented: contrast curves include small-sample corrections and self-subtraction estimates; the RV detection limits for HIP 36277 are derived via injection-recovery; and the background/companion status of detected objects is checked against Gaia astrometry. The main quantitative conclusions, however, rest on the single-companion circular-orbit assumption of Eq. (1) and on the choice of atmospheric models, so the quoted mass/separation ranges are less robust than the abstract implies.","major_comments":[{"comment":"The mass–separation curves that determine the headline constraints for HIP 11696 (2.5–28 au, 4–16 MJup) and HIP 47110 (3–30 au, ~3–10 MJup) are derived from Eq. (1), which assumes a single companion on a circular orbit. The text in Section 4.2 states that the resulting masses are minimum values, but this is not a rigorous lower bound: for an eccentric orbit the instantaneous proper-motion anomaly depends on orbital phase, so a given companion mass can produce a larger or smaller PMa than the circular-orbit value, and a superposition of two or more companions would lower the mass attributable to each individual body. Because the paper does not test how the PMa curve shifts under these alternatives, the intersections with the DI mass limits (and therefore the quoted upper separation limits of 28 au and 30 au) could change substantially. The abstract and Section 7 report the ranges without this qualification, so an explicit sensitivity analysis or a softened statement of the constraints is needed.","section":"Section 4.2, Eq. (1), Figures 6–8"},{"comment":"The DI mass limits used in the final comparison (Figures 6–8) are obtained from the AMES-COND models only, as stated in Section 5.4. However, Figure 5 shows that the BEX cold-start models give significantly less restrictive (higher) mass limits at the separations of interest. Since the upper separation limits (28 au and 30 au) are defined by where the PMa-required mass crosses the DI limit, adopting cold-start models would move these crossings to smaller separations and narrow the allowed mass ranges. The paper justifies the AMES-COND choice by reference to hot-start models being in better agreement with observations, but it does not quantify the sensitivity of the quoted bounds to this choice. Please either provide a quantitative comparison or state the quoted ranges as conditional on the adopted hot-start/AMES-COND models.","section":"Section 5.4, Figures 5–8"}],"minor_comments":[{"comment":"The references in Section 6 to \"the orange line in Figure 7\" and \"the green line in Figure 7\" for the HIP 36277 age cases appear to be incorrect; the HIP 36277 plots are in Figure 8, not Figure 7.","section":"Section 6"},{"comment":"In the sentence \"The PMa signal obtained by Kervella et al. (2022) for this star have a SNR of 3.12\", the verb should agree with the singular subject \"signal\" (i.e., \"has\").","section":"Section 3.3"},{"comment":"The caption phrase \"On the right of each plots\" should be \"On the right of each plot\".","section":"Figure 4 caption"},{"comment":"The sentence \"In the latter case, as detailed in the text we could use just a lower number of models\" is awkward; consider rephrasing for clarity.","section":"Section 5.3"}],"recommendation":"major_revision","confidential_remarks":"The paper is a competent instrumental science demonstration, and the central constraints are likely correct in spirit. The main revision needed is a sensitivity analysis of the PMa-to-mass conversion to eccentricity/multiplicity and an explicit model-dependence caveat. If the authors address these, I would support publication. The paper fits MNRAS's scope."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"This paper is a straightforward high-contrast imaging follow-up of three Gaia proper-motion anomaly (PMa) stars, and it does what it claims. The genuinely new elements are the first SHARK-NIR high-contrast observations and the simultaneous dual-arm operation with LMIRCam. The constraints for HIP 11696 and HIP 47110 are well derived from contrast curves, RUWE limits, and the Kervella PMa relation. I appreciate the care: the bright object around HIP 11696 is correctly identified as a background source via multi-epoch astrometry, the outer companion of HIP 36277 is confirmed as bound using Gaia, and the inner candidate is properly hedged as low-SNR and not detected in L'. The authors also consider both young and old ages for HIP 36277, which is the right way to handle that ambiguity.\n\nThe main soft spot is the reliance on Eq. 1, which assumes a single companion on a circular orbit. The paper states that masses are minimum values, but that is not a strict lower bound: for an eccentric orbit, a given mass can produce a larger or smaller PMa depending on orbital phase, and the quoted ranges could shift. There is no sensitivity test. I would like to see a paragraph on how the 4–16 M_Jup and 2.5–28 au ranges change for moderate eccentricities or if the signal is split among multiple bodies. That said, the qualitative conclusion—a companion between a few and ~30 au—is robust because the outer boundary is anchored by the DI detection limits and the inner boundary by RUWE. So this is a caveat to address, not a fatal flaw.\n\nMinor points: data are available only on request, which is common but slightly annoying. The vector PMa maps in Figure 9 are a useful finding chart, though the authors themselves note they are rough.\n\nOverall, this is incremental but solid work. The first SHARK-NIR science results are of genuine interest to the high-contrast imaging community, and the constraints on these three stars are new and usable. It deserves peer review. I would send it to a referee with a request to probe the eccentricity sensitivity, but the paper is publishable after that discussion.","headline":"Solid first-light science from SHARK-NIR that places useful mass-separation constraints on two PMa stars and a candidate around a third; the main caveat is the circular-orbit PMa conversion, which the paper flags but does not stress-test.","tokens_in":18714,"tokens_out":1666,"would_cite":true,"duration_ms":19297,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"Simultaneous near-infrared and thermal-infrared coronagraphic imaging of three accelerating stars constrains the unseen companions of HIP 11696 and HIP 47110 to planetary masses at 2.5–28 au and 3–30 au, and shows that HIP 36277's wide…","keywords":["proper motion anomaly","high-contrast imaging","coronagraphy","exoplanet detection","Gaia astrometry","HIP 11696","HIP 47110","HIP 36277"],"falsifier":"A direct detection of a companion around HIP 11696 or HIP 47110 at a separation outside 2.5–28 au or 3–30 au with a mass consistent with the anomaly, or an astrometric or radial-velocity measurement showing that the orbit is eccentric rather than circular, would overturn the claimed constraints.","tokens_in":17524,"feed_emoji":"🪐","tokens_out":7411,"duration_ms":71346,"temperature":0.7,"pith_summary":"This paper tries to pin down the mass and orbital distance of the unseen companions responsible for the measured proper-motion anomalies of three nearby stars, using very deep coronagraphic images taken simultaneously in two infrared bands. For HIP 11696 and HIP 47110, excluding companions at large separation and at very small separation leaves a narrow allowed window: 2.5–28 au with mass 4–16 Jupiter masses for the first, and 3–30 au with mass 3–10 Jupiter masses for the second. For HIP 36277 the situation is age-dependent: a bright bound companion was imaged, and a faint inner candidate could explain the anomaly if the system is young. The value is that even non-detections, combined with astrometric acceleration, can identify the most promising architectures for future direct imaging.","feed_headline":"Two nearby stars host unseen 4-16 Jupiter-mass planets","feed_subtitle":"Deep imaging rules out wide companions, pinning the unseen planets to separations of 2.5-28 au and 3-30 au.","key_machinery":"The load-bearing machinery is the proper-motion anomaly, the difference between short-term and long-term proper motion, which reveals the gravitational pull of an unseen companion. The mass–separation conversion $m_2(r)=\\frac{\\sqrt{2\\epsilon_i}}{\\varpi r}\\,m_1$ translates the Gaia astrometric excess noise into a companion mass at each assumed orbital radius, under the assumption of a single circular orbit. This curve is then clipped from below by RUWE-based short-separation exclusion, and from above by the contrast limits of the two simultaneously operating coronagraphic cameras; the surviving window is the claimed companion parameter space. A second mechanism, the position angle of the proper-motion-anomaly vector, produces an allowed-position map on the sky that is used to test whether an imaged companion can actually be the source.","core_discovery":"The central claim is that the proper-motion anomalies of HIP 11696 and HIP 47110 are produced by single, unseen, planetary-mass companions on roughly circular orbits: for HIP 11696 the companion lies at 2.5–28 au with mass 4–16 Jupiter masses, with the highest masses only at the outer part of that range; for HIP 47110 the companion lies at 3–30 au with mass 3–10 Jupiter masses. These intervals come from intersecting three independent constraints: the proper-motion-anomaly mass–separation relation derived from Gaia excess noise, RUWE-based exclusions of very close companions, and contrast limits from high-contrast imaging that exclude wider and more massive companions. For HIP 36277 the paper reports a bound companion at about 1.95 arcseconds and a fainter candidate at 0.625 arcseconds; depending on whether the star is young or old, one or the other could account for the magnitude of the anomaly, but the position angle of the outer companion rules it out as the source, leaving the inner candidate, if real, or an unseen companion.","pith_inferences":["A testable consequence the authors leave implicit is that if future Gaia releases or radial-velocity monitoring show the excess noise changing with time, the single-circular-companion hypothesis would be disfavored and the quoted mass intervals would need revision.","The allowed-position maps used for HIP 36277 could serve as finding charts for a dedicated campaign at 0.05–0.6 arcseconds with starlight-suppression techniques, either revealing the companions or pushing their minimum masses upward.","The same pipeline could be applied systematically to the rest of the high-signal-to-noise proper-motion-anomaly catalogue, which would clarify how common 3–16 Jupiter-mass planets at 3–30 au are around nearby young stars."],"forward_implications":["If the circular-orbit interpretation is right, HIP 11696 and HIP 47110 each host a giant planet at separations of roughly 0.05–0.6 arcseconds, at the edge of what current high-contrast imagers can reach, so deeper observations could image them directly.","The allowed windows are narrow enough that a single additional epoch of astrometry, or a better contrast curve, should either detect the companion or further shrink the parameter space.","For HIP 36277, the wide bright companion cannot be the source of the proper-motion anomaly regardless of its mass, so the system's age must be settled before the inner candidate can be assigned a definitive mass.","The simultaneous H-band and L'-band strategy improves mass limits in different separation ranges, so future surveys of accelerating stars should use parallel wavelength coverage.","The methods used here can be applied to the dozens of other proper-motion-anomaly candidates with signal-to-noise between 3 and 20, turning null detections into useful constraints."],"supporting_citations":[{"why":"Supplies the Eq. 18 mass–separation relation from Gaia excess noise that the paper uses as its Eq. 1.","marker":"Kervella et al. (2019)"},{"why":"Provides the Hipparcos-Gaia proper-motion-anomaly catalogue from which the three targets and their anomaly values are drawn.","marker":"Kervella et al. (2022)"},{"why":"Provides the Gaia distances, parallaxes, and common proper motion that confirm the bound companion around HIP 36277.","marker":"Gaia Collaboration et al. (2023)"},{"why":"Defines the RUWE statistic used to set short-separation exclusions for HIP 11696 and HIP 47110.","marker":"Lindegren et al. (2021)"},{"why":"Supplies the AMES-COND atmospheric models used to convert detected photometry into companion masses.","marker":"Allard et al. (2003)"},{"why":"Provides the position-angle-based method used to build the allowed-position maps for the companions.","marker":"Bonavita et al. (2022)"},{"why":"Supplies the earlier astrometry identifying the HIP 11696 object as background, which the new data confirm.","marker":"Galicher et al. (2016)"},{"why":"Defines the angular differential imaging technique used in the data reduction to reach the reported contrasts.","marker":"Marois et al. (2006)"}],"fun_headline_variants":["Two nearby stars host hidden planets of 4-16 and 3-10 Jupiter masses","Unseen 4-16 and 3-10 Jupiter-mass planets found around two nearby stars","Hidden giant planets of 4-16 and 3-10 Jupiter masses orbit two stars","Two stars' motion anomalies reveal unseen companions of 4-16 and 3-10 Jupiter masses"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The core assumption is that the entire proper-motion anomaly is caused by a single companion on a circular orbit; if the orbit is eccentric or several bodies contribute, the quoted mass and separation ranges do not follow.","fun_headline_variants_meta":{"raw":{"variants":["Two nearby stars host hidden planets of 4-16 and 3-10 Jupiter masses","Unseen 4-16 and 3-10 Jupiter-mass planets found around two nearby stars","Hidden giant planets of 4-16 and 3-10 Jupiter masses orbit two stars","Two stars' motion anomalies reveal unseen companions of 4-16 and 3-10 Jupiter masses"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000497,"raw_usage":{"total_tokens":2502,"prompt_tokens":1081,"completion_tokens":1421,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":697,"completion_tokens_details":{"reasoning_tokens":1323}},"tokens_in":697,"tokens_out":1421,"duration_ms":12333,"temperature":1.0,"reasoning_tokens":1323,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-11T21:40:04.462174+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A direct detection of a companion around HIP 11696 or HIP 47110 at a separation outside 2.5–28 au or 3–30 au with a mass consistent with the anomaly, or an astrometric or radial-velocity measurement showing that the orbit is eccentric rather than circular, would overturn the claimed constraints.","supporting_citations":[{"cited_title":"H., Schweitzer A., Alexander D","cited_arxiv_id":null,"evidence_quote":"Supplies the AMES-COND atmospheric models used to convert detected photometry into companion masses."}],"review_version":1}