{"id":"0e0e0cb4-bfe8-421d-b72a-357ecd8753a3","arxiv_id":"2606.19671","paper_version":1,"verdict":"UNVERDICTED","confidence":"LOW","novelty_score":4.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"No bursty planet-induced radio emission detected from five inactive M dwarfs; upper limits constrain GJ 367 b magnetosphere to <0.8 G under assumed stellar wind conditions.","lead":"Astronomers searched five nearby M dwarf stars with close-in rocky planets for radio bursts caused by star-planet magnetic interactions at GHz frequencies but found none. The resulting upper limits on possible planet magnetic fields depend on assumptions about the stars' winds and point toward lower-frequency searches with new telescopes.","discovery_kind":"new_application","skeptic_critique":{"model":"grok-4.3","headline":"GJ 367 b field upper limit (<0.8 G) and \"no extended magnetosphere\" rest on stellar wind n and v inferred from rotation period via scaling relations","rationale":"The reader's weakest assumption is exactly the load-bearing step for the central quantitative claim. The paper itself states the dependence, so the issue is transparent rather than hidden; no additional internal inconsistency is evident from the supplied text.","tokens_in":1816,"tokens_out":297,"duration_ms":11479,"concrete_test":"Recompute the GJ 367 b magnetosphere size and B_p upper limit while varying stellar wind density and velocity over the range 0.1–10× the nominal values used in the paper (keeping other parameters fixed); report the new B_p bound and whether an extended magnetosphere remains excluded.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The non-detection to magnetosphere mapping requires the stellar wind ram pressure and Alfvén surface to set the interaction geometry and Poynting flux available for radio emission. These quantities are obtained from empirical P_rot–wind relations rather than direct measurement or in-situ constraints; a factor-of-several change in density or velocity (plausible given M-dwarf wind uncertainties) shifts the implied planetary field bound by a comparable factor and can permit an extended magnetosphere. The paper flags the dependence but the headline quantitative claim is only as secure as those adopted wind values.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.3","summary":"The paper reports GHz radio observations of five slowly rotating M dwarfs with transiting terrestrial planets, finding no bursty star-planet interaction (SPI) emission but detecting quiescent emission from LHS 3844 and LHS 1678. From the non-detections it derives upper limits on planet-induced radio flux and, under assumptions about stellar winds, infers constraints on exoplanet magnetospheres, with the strongest limit being no extended magnetosphere and B_p < 0.8 G for GJ 367 b. The work also notes persistent magnetic activity at Gyr ages and discusses tensions with literature SPI candidates, favoring sub-GHz searches.","tokens_in":1967,"tokens_out":495,"duration_ms":18134,"significance":"If the central non-detection results hold, the paper supplies useful observational upper limits on GHz SPI and identifies targets for future radio transit experiments. The quiescent detections add to the record of magnetic activity in old, low-variability M dwarfs. The discussion of model-dependent magnetosphere bounds and the call for better stellar-wind constraints are constructive, though the quantitative field-strength claim is only as robust as the adopted wind parameters.","major_comments":[{"comment":"The section deriving the GJ 367 b magnetosphere constraints (the paragraph stating 'GJ 367 b has the tightest constraints -- no extended magnetosphere and an exoplanet field <0.8 G'): the reported quantitative bound relies on specific stellar wind density and velocity values inferred from rotation-period scaling relations rather than direct measurement. The manuscript notes the dependence but does not propagate plausible uncertainties in these parameters (which can shift the bound by a factor of several) or present a range of allowed field strengths under different wind conditions; this makes the headline numerical limit load-bearing on unverified external inputs.","section":"GJ 367 b magnetosphere constraints paragraph"}],"minor_comments":[{"comment":"The abstract and introduction could more explicitly separate the direct observational non-detections from the subsequent model-dependent interpretation of magnetosphere size and field strength.","section":"Abstract"},{"comment":"Notation for stellar wind parameters (n, v) and the Poynting flux calculation should be defined once in a dedicated methods subsection rather than introduced inline in the results.","section":"Methods/Results transition"}],"recommendation":"major_revision","confidential_remarks":null},"author_rebuttal":{"model":"grok-4.3","summary":"We thank the referee for their constructive review and for recognizing the value of our non-detections and quiescent detections. We address the single major comment below and will incorporate revisions to improve the presentation of the magnetosphere constraints.","responses":[{"response":"We agree that explicitly propagating uncertainties in the adopted stellar wind parameters and presenting a range of allowed exoplanet field strengths would make the constraint more robust and transparent. Although the manuscript already states that the results 'depend strongly on unknown stellar wind parameters inferred from stellar rotation period,' we did not quantify the effect of plausible variations. In the revised manuscript we will add a short discussion (and possibly a small table or figure inset) showing how the <0.8 G limit shifts under wind densities and velocities that differ by factors of a few, consistent with the scatter reported in the rotation-period scaling literature. This will contextualize the headline number without altering the central non-detection result.","revision_made":"yes","referee_comment":"[GJ 367 b magnetosphere constraints paragraph] The section deriving the GJ 367 b magnetosphere constraints (the paragraph stating 'GJ 367 b has the tightest constraints -- no extended magnetosphere and an exoplanet field <0.8 G'): the reported quantitative bound relies on specific stellar wind density and velocity values inferred from rotation-period scaling relations rather than direct measurement. The manuscript notes the dependence but does not propagate plausible uncertainties in these parameters (which can shift the bound by a factor of several) or present a range of allowed field strengths under different wind conditions; this makes the headline numerical limit load-bearing on unverified external inputs."}],"tokens_in":1488,"tokens_out":351,"duration_ms":21642,"standing_objections":[]},"desk_editor":{"model":"grok-4.3","letter":"The main point is that this paper gives new GHz radio data on five slowly rotating M dwarfs with short-period planets and reports no bursty star-planet interaction signals across multiple orbits. Two stars show quiescent emission instead.\n\nThe observations themselves are the concrete addition. The authors cover full orbital periods for each target and derive flux upper limits that translate into magnetosphere constraints for the planets. They also flag the tension with earlier candidate detections and suggest sub-GHz searches as the better path forward.\n\nThe soft spot is the step from non-detection to planetary field strength. The <0.8 G bound and \"no extended magnetosphere\" statement for GJ 367 b use stellar wind density and velocity taken from rotation-period scaling relations. The paper notes the dependence, but those inputs are not measured in the data, so a plausible change in wind properties moves the limit by a similar factor. The raw non-detection result stands on its own; the numerical field claim does not.\n\nThis work is for people already following radio searches for exoplanet magnetism. A reader who needs fresh limits on these specific systems or wants to see how the beaming and frequency arguments play out will find it useful. The methods for the observations look standard and the caveats are stated plainly.\n\nI would send it for peer review. The data are new and the limitations are handled honestly.","headline":"New GHz observations of five M dwarfs yield non-detections of planet-induced emission and some new upper limits, but the tightest quantitative claim rests on unmeasured stellar wind parameters.","tokens_in":2490,"tokens_out":355,"would_cite":false,"duration_ms":17518,"reading_group":"maybe","serious_thinker":"yes","would_accept_peer_review":true},"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.3","headline":"Non-detections of GHz radio emission from M dwarfs with close-in planets constrain the exoplanets' magnetic fields to be weak or absent under modeled wind conditions.","keywords":["exoplanet magnetospheres","M dwarfs","star-planet interaction","radio observations","GHz emission","GJ 367 b","stellar winds","transiting planets"],"falsifier":"A direct measurement of the stellar wind parameters for GJ 367's host star that shows density or velocity values differing enough from the rotation-based estimates to raise the allowable exoplanet field strength above 0.8 G.","tokens_in":2728,"feed_emoji":"📡","tokens_out":818,"duration_ms":19922,"temperature":0.7,"pith_summary":"The paper reports targeted GHz observations of five slowly rotating M dwarfs with transiting terrestrial planets, covering their full sub-day orbital periods. No bursty emission from sub-Alfvénic star-planet interaction was detected, although quiescent emission was seen from two of the stars. The non-detections are converted into quantitative upper limits on the planets' magnetospheres by assuming the emission would have been detectable if the planets possessed strong enough fields to stand off the stellar wind. The tightest bound applies to GJ 367 b, which is limited to no extended magnetosphere and a field strength below 0.8 G. These results rest on stellar wind parameters inferred from rotation period, and the authors note that the systems' close orbits make the non-detections surprising relative to literature candidates.","feed_headline":"GHz non-detections limit GJ 367 b field to under 0.8 G","feed_subtitle":"Observations of five M dwarfs with close planets find no SPI bursts, yielding magnetosphere bounds that depend on modeled stellar winds.","key_machinery":"The sub-Alfvénic star-planet interaction (SPI) mechanism that can produce radio emission when a planet's magnetosphere interacts with the stellar wind, combined with conversion of flux-density upper limits into field-strength bounds using modeled wind density and velocity.","core_discovery":"The central claim is that the absence of detectable planet-induced radio emission at GHz frequencies from these systems allows constraints on exoplanet magnetic fields via the sub-Alfvénic interaction model, specifically for GJ 367 b yielding a field upper limit of 0.8 G and no extended magnetosphere, although this depends on stellar wind parameters derived from rotation periods. The detections of quiescent emission in two stars indicate ongoing magnetic activity despite their ages and low variability.","pith_inferences":["Direct measurements of stellar wind parameters for these specific M dwarfs would test whether the derived field limits are robust or artifacts of the rotation-period scaling.","If non-detections persist at lower frequencies, many reported radio SPI candidates may originate from stellar activity rather than planets.","The two stars with quiescent radio detections could be used as targets for radio transit searches to separate planetary from stellar signals.","The approach highlights the value of combining radio non-detections with independent constraints on stellar winds to refine exoplanet magnetosphere statistics."],"forward_implications":["If the non-detections are due to insufficient flux density rather than beaming or frequency cutoff, the planets lack extended magnetospheres.","GJ 367 b is limited to a magnetic field below 0.8 G with no extended magnetosphere under the assumed wind conditions.","The observed systems have orbital distances that should favor SPI more than most literature candidates, creating a tension that requires either favorable wind or geometry conditions on the candidates or a non-SPI explanation for those detections.","The results support shifting future searches for radio SPI to sub-GHz frequencies with sensitive arrays such as MeerKAT."],"fun_headline_variants":["GHz non-detections set GJ 367 b field upper limit at 0.8 G","M dwarf observations find no planet-induced GHz radio emission","Planet magnetosphere constrained by M dwarf radio non-detections","No bursty emission detected from M dwarfs with close planets"],"cache_read_input_tokens":2112,"weakest_assumption_plain":"The stellar wind density and speed are correctly estimated from the stars' rotation periods rather than measured directly.","fun_headline_variants_meta":{"raw":{"variants":["GHz non-detections set GJ 367 b field upper limit at 0.8 G","M dwarf observations find no planet-induced GHz radio emission","Planet magnetosphere constrained by M dwarf radio non-detections","No bursty emission detected from M dwarfs with close planets"]},"model":"grok-4.3","cost_usd":0.009434,"raw_usage":{"total_tokens":4270,"prompt_tokens":778,"num_sources_used":0,"completion_tokens":71,"cost_in_usd_ticks":94337000,"prompt_tokens_details":{"text_tokens":778,"audio_tokens":0,"image_tokens":0,"cached_tokens":256},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":3421,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":778,"tokens_out":71,"duration_ms":18870,"temperature":1.0,"reasoning_tokens":3421,"cache_read_input_tokens":256,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-06-26T16:11:42.049788+00:00","model_set":{"reader":"grok-4.3"},"falsifier":"A direct measurement of the stellar wind parameters for GJ 367's host star that shows density or velocity values differing enough from the rotation-based estimates to raise the allowable exoplanet field strength above 0.8 G.","supporting_citations":[],"review_version":1}