{"id":"6c2a8e5b-ec81-49b5-b8a1-3e2030012c51","arxiv_id":"2504.19849","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":7,"one_line_summary":"JWST observations of comet C/2017 K2 reveal a water-dominated hyperactive coma, a nucleus smaller than 4.2 km, a dust crystalline fraction of about 0.384, and residual 3 to 8 micron emission attributed to PAHs.","lead":"JWST spectra of Oort Cloud comet C/2017 K2 show strong emission from water, carbon monoxide, carbon dioxide, and many trace molecules, plus dust whose submicron grains are about 38% crystalline. The comet looks hyperactive, with a nucleus no larger than 4.2 km in radius, and residual glow at 3 to 8 microns hints at soot-like PAH molecules.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The hyperactivity claim is directly supported only by the 5 µm hot-band Q(H2O)=7.6e28 s⁻¹; the paper's own MRS ν₂-band values are 3–8 times lower, and recomputing the active fraction with those values gives roughly 11–30%, not >86%.","rationale":"Both the reader and I locate the weakest point in the same place. The central observational detections are credible; the tension is in the derived global water production rate. I considered whether the nucleus radius upper limit or the dust/PAH modeling might be more load-bearing, but the radius is an upper limit (so the active fraction is a lower limit for a fixed Q), and the PAH/dust claims are already hedged as model-dependent. The water production discrepancy is different: it is a factor 3–8 internal inconsistency in the quantity that directly sets the headline value, and the authors explicitly leave it unresolved. The analytical rescaling is unambiguous, so the concern lands and confirms the CONDITIONAL verdict.","tokens_in":49063,"tokens_out":4851,"duration_ms":49018,"concrete_test":"Recompute the active fraction from Table 3 formula using the MRS terminal values reported in Section 4.4: with Q(H2O)=2.64e28 s⁻¹ (off-nucleus) and 0.967e28 s⁻¹ (on-nucleus), Z=3.9e20 s⁻¹ m⁻², and R=4.2 km, evaluate f=Q/(4πR²Z). If f is approximately 30% and 11%, the >86% hyperactivity claim is unsupported. A stronger confirmation would be a simultaneous non-LTE radiative-transfer fit to both the 5 µm hot bands and the 6.3 µm ν₂ band; if the best global Q converges to the lower MRS value, the abstract's first claim should be revised.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The abstract's first derived result—hyperactivity with water ice active fraction ≥86%—rests entirely on Q(H2O)=7.6e28 s⁻¹ from NIRSpec 5 µm hot-band lines (Table 2) and the nucleus upper limit R<4.2 km. Section 4.4/Figure 8a reports MRS 6.3 µm ν₂-band fits giving 0.967e28 s⁻¹ on-nucleus and 2.64e28 s⁻¹ off-nucleus; the paper states the factor-3–8 discrepancy 'is not explained, requiring further investigation beyond the scope.' Because A=Q/Z and f=A/(4πR²), f scales linearly with Q: with Z=3.9e20 s⁻¹ m⁻² and R=4.2 km, Q=2.64e28 gives f≈30%, and Q=0.967e28 gives f≈11%. Under the paper's own hyperactive threshold (>50%), neither case is hyperactive. Ground-based IRTF Q(H2O)=3.65e28 (Section 5.3) is consistent with the MRS value, not with 7.6e28. The large-beam OH 18-cm rate (~2e29) is cited as evidence for extended water release, but it samples a much larger coma and does not justify adopting the 5 µm value as the global Q for the active-fraction calculation. Thus the most prominent result of the abstract is not robust unless the band discrepancy is resolved by a mechanism that specifically makes the 5 µm hot bands trace a larger global production rate than the ν₂ band.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"This paper presents JWST NIRSpec (G395M) and MIRI MRS IFU observations of the Oort Cloud comet C/2017 K2 at a heliocentric distance of 2.35 au, with spectra extracted in a 1-arcsec aperture and in a 3x3 grid of spatial beams. The authors report detections of H2O (both 5 µm hot bands and 6.3 µm nu2 band), 12CO, 13CO, CO2, and numerous trace species (CN, H2CO, CH3OH, CH4, C2H6, HCN, NH2, OH prompt emission), and map their spatial distributions. From radial profiles and WebbPSF models they derive a nucleus radius upper limit of <4.2 km. Using the NIRSpec 5 µm water hot-band production rate Q(H2O)=7.6e28 s^-1, they compute a water ice active fraction >86% and label the comet hyperactive. Thermal modeling of the 7-27 µm MRS SED yields a coma dust composition dominated by amorphous carbon, amorphous olivine and pyroxene, and Mg-rich crystalline olivine, with a crystalline mass fraction fcryst=0.384±0.065. Residuals after subtracting continuum, scattered light, and molecular models exhibit features at 3.42, 6.35, 6.92, and 8.25 µm attributed to PAHs, modeled with the Ames PAH database.","tokens_in":49336,"tokens_out":6827,"duration_ms":61183,"significance":"If the results hold, this is a valuable JWST dataset: it demonstrates the power of IFU spatial-spectral mapping of a comet coma, provides a rich molecular inventory with spatial distributions, constrains the nucleus size, and offers a new data point for comet dust mineralogy. The reductions are detailed and the molecular detections are supported by model fits. The paper is honest about several limitations, notably the unexplained factor 3-8 discrepancy between Q(H2O) values from the 5 µm hot bands and the 6.3 µm nu2 band. However, the abstract's headline claims—hyperactivity and high crystalline dust fraction—are not robust to the model assumptions that the paper itself documents. The hyperactivity claim scales linearly with the adopted Q(H2O); using the MRS values would place the active fraction at 11-30%, below the >50% hyperactivity threshold. The dust composition is derived from one of three thermal model treatments selected by an AIC comparison with inflated uncertainties, and the fcryst value varies from 0.36 to 0.65 depending on position and model case.","major_comments":[{"comment":"The hyperactivity claim in the abstract and Section 6 (active fraction >86%) rests entirely on the NIRSpec 5 µm hot-band water production rate Q(H2O)=7.6e28 s^-1 (Table 2), while the MRS 6.3 µm nu2-band fits give Q(H2O)=(0.967 to 2.64)e28 s^-1 (Figure 8a). The paper states that the discrepancy 'is not explained, requiring further investigation which is beyond the scope of this paper.' Because the active fraction f = A/(4πR^2) scales linearly with Q, using the MRS values with the same nucleus radius (4.2 km) gives f ≈ 11-30%, below the >50% hyperactivity threshold. The ground-based IRTF value (3.65e28 s^-1) agrees with the MRS rather than the NIRSpec value. The abstract's first derived result is therefore not supported unless the band discrepancy is resolved by a mechanism that specifically makes the 5 µm hot bands trace the global water production. I recommend that the hyperactivity claim be removed or reframed as a conditional result pending reconciliation of the water bands.","section":"§4.4, Figure 8a; §6, Table 3"},{"comment":"The quoted crystalline mass fraction fcryst=0.384±0.065 is the mean over the seven Case A 'AO50' thermal models, but this value depends strongly on the model treatment. The center position (0:0) gives fcryst=0.52 for Case A and Case B and 0.65 for Case C (Table 5), while the other six positions give 0.361±0.034; the spread between cases is comparable to the quoted uncertainty and is not included in the error budget. The 'AO50' model was selected over 'AP50' and the first-order model by fitting with uncertainties artificially inflated by a factor of 40 in two spectral regions (Section 7.1-7.2). Because the abstract presents fcryst as a single value without these caveats, the authors should either report the model-case dependence explicitly in the abstract or present fcryst as a range.","section":"§7.3-7.4, Tables 4-5, Figures 16-17"},{"comment":"The PAH identification relies on the residual F_PAH = F_obs - F_thermal - F_scattered, where the thermal model was itself refit after subtracting a first estimate of the PAH emission (Appendix B: 'This process is iterative'). This introduces circularity: the residual features are not independent of the model assumptions about the continuum, the scattered-light slope, and the molecular contributions. The paper also notes that the CH3OH nu9 band, which is not in the spectral model, contributes to the 3.42 µm residual (Section 8). To substantiate the 'strongly suggests' claim, the authors should demonstrate the stability of the residual features under plausible variations of the scattered-light slope and thermal model weighting (e.g., using the AP50 model or a different thermal fit), and quantify the CH3OH contribution. Without such tests, the PAH detection should be described as tentative rather than as a strong suggestion.","section":"§8, Appendix B, Figure 22"}],"minor_comments":[{"comment":"The abstract and Section 6 use 'greater than or equal to 86%' while Table 3 and the text also say '>86%'; please standardize.","section":"Abstract, §6, Table 3"},{"comment":"The figure caption spells the comet as 'C/20217 K2 (PanSTARRS)' and Section 8 has 'C.2017 K2'; both are typos.","section":"Figure 3 caption; Section 8"},{"comment":"The text states that the 5 µm hot-band values are higher 'by a factor ∼2' than the 6.3 µm band, but the values in Figure 8a differ by factors of about 3 to 8 (7.6e28 vs 2.64e28 and 0.967e28); the text should state the full range.","section":"§4.4, Figure 8a"},{"comment":"The note says 'radius of <4.3 km' while the abstract and Section 3 quote <4.2 km; the appropriate value should be used consistently.","section":"Table 3 note"},{"comment":"The factor-1000 flux scaling to emulate optically thin conditions is a heuristic; its effect on the retrieved production rates and their uncertainties should be stated explicitly in the text rather than only in the caption of Figure 10.","section":"§5.1"},{"comment":"The paper would benefit from a brief discussion of how the single NIRSpec dither position affects the reliability of the NIRSpec spatial maps and the 5 µm water production rate.","section":"§2"}],"recommendation":"major_revision","confidential_remarks":"The paper is data-rich and the molecular detections are likely solid, but the most prominent claim in the abstract is not robust to the paper's own internal analysis. I recommend the authors reframe the hyperactivity claim as conditional on the unresolved water-band discrepancy, and present the dust fcryst and PAH residuals with explicit model-dependence caveats. The paper would then be a strong contribution to the JWST comet literature."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"First thing you should know: this paper is worth engaging with for the dataset, not for the abstract. The JWST IFU spectra of C/2017 K2 are genuinely new and valuable — 2.9–28 µm coverage, spatial-spectral maps of H2O, CO2, CO, 13CO, CH4, CH3OH, C2H6, HCN, CN and more, with careful PSG fits and a plausible 12C/13C profile. Those detections and the maps are solid, and the authors are admirably transparent about their methods and caveats.\n\nThe soft spot is the first headline result. The active fraction of >86% is computed with Q(H2O)=7.6e28 s^-1 from NIRSpec 5 µm hot-band lines, but the MRS 6.3 µm ν2 band fits give 0.97–2.64e28 s^-1 (Figure 8a). The paper states this factor-of-3–8 discrepancy 'is not explained' and defers it. That matters because the active fraction scales linearly with Q. Using the MRS values would put K2 at ~11–30% — not hyperactive by the paper's own >50% threshold. The ground-based IRTF value also matches MRS, not NIRSpec. So the abstract's first result is not robust; it is a model-dependent choice that happens to maximize the headline.\n\nThe dust composition and PAH results have a similar issue, though less severe because the paper flags them as model-dependent. The fcryst=0.384 and the PAH residuals come from an iterative thermal-model subtraction with uncertainty inflation in selected wavelength regions and a PAH fit library. The authors note the 4–5 µm hump and that the best-fit PAH model was rejected. That is honest, but it means these numbers should be read as 'consistent with' rather than 'detected'. The molecular detections are on much firmer ground.\n\nWho is this for? Cometary spectroscopists and anyone using JWST IFU data on small bodies. The dataset and Q-curves will be a reference for years. But a serious referee should insist on major revision: either explain or caveat the water-band discrepancy in the abstract, and demote the PAH and crystalline-fraction claims to exploratory. If the authors fix the framing, this becomes a strong paper. I would send it out.","headline":"The JWST spectra are a real step forward for cometary science, but the headline 'hyperactive' claim rests on a water production rate that the paper's own MRS data contradict by a factor of 3-8.","tokens_in":50078,"tokens_out":2462,"would_cite":true,"duration_ms":25445,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"JWST spectroscopy of Oort Cloud comet C/2017 K2 (PanSTARRS) shows a hyperactive nucleus under 4.2 km across, crystalline-silicate-rich dust, and probable PAH emission in the coma.","keywords":["C/2017 K2 (PanSTARRS)","hyperactive comet","Oort Cloud comet","water production rate","coma dust composition","crystalline silicates","polycyclic aromatic hydrocarbons","JWST infrared spectroscopy"],"falsifier":"A radiative-transfer calculation of the optically thick H$_2$O 6.3 $\\mu$m $\\nu_2$ band along the actual JWST lines of sight, using opacity-corrected excitation models, would decide the matter: if the corrected 6.3 $\\mu$m rate stays near 1 to 2.6$\\times10^{28}$ s$^{-1}$ rather than converging to $7.6\\times10^{28}$ s$^{-1}$, the active fraction falls to roughly 10 to 30% and the hyperactivity claim is refuted. A second, independent check is a new JWST observation of the comet at a different heliocentric distance to see whether the hot-band-to-$\\nu_2$ ratio persists or whether the discrepancy was an aperture or opacity artifact.","tokens_in":48730,"feed_emoji":"☄️","tokens_out":13462,"duration_ms":116050,"temperature":0.7,"pith_summary":"This paper analyzes JWST near- and mid-infrared spectra of the inner coma of Oort Cloud comet C/2017 K2 (PanSTARRS) at a heliocentric distance of 2.35 au and argues that the comet is hyperactive: its measured water output requires at least 86% of the surface of a nucleus smaller than 4.2 km in radius to be sublimating, which implies a substantial distributed source of water-ice grains in the coma beyond direct nucleus sublimation. The same data yield a dust inventory for the sub-micron grains that is roughly 39% crystalline olivine by mass, with a crystalline mass fraction $f_{\\rm cryst} = 0.384 \\pm 0.065$, and residual emission features in the 3 to 8 $\\mu$m region that the authors argue are best explained by small, hydrogenated polycyclic aromatic hydrocarbons. A full volatile census (H$_2$O, $^{12}$CO, $^{13}$CO, CO$_2$, CN, H$_2$CO, CH$_3$OH, CH$_4$, C$_2$H$_6$, HCN, NH$_2$, and OH prompt emission) is reported, together with a water ortho-to-para ratio of at least 2.75. The paper's own analysis flags that the water production rate derived from the 5 $\\mu$m hot bands is about twice the rate from the optically thick 6.3 $\\mu$m band, and that this discrepancy is not explained; the hyperactivity claim depends on the higher value.","feed_headline":"JWST finds comet K2 is hyperactive with a tiny nucleus","feed_subtitle":"At 2.35 au water ice covers ≥86% of a <4.2-km nucleus, with crystalline dust and PAHs in the coma.","key_machinery":"The argument is carried by three analytical instruments. First, a nucleus upper-limit procedure: azimuthally averaged radial surface-brightness profiles in dust-continuum windows are fit with power laws, and comparison with a point-spread-function-convolved coma and a combined coma-plus-nucleus model sets a conservative 30/70 nucleus-to-coma flux threshold that translates, through a thermal model of an insolation-heated sphere, into a nucleus radius below 4.2 km. Second, molecular fluorescence modeling: optically thin fluorescence excitation models with a Haser density profile and a 0.52 km/s expansion velocity are fit to the water $\\nu_2$ 6.3 $\\mu$m band and the 5 $\\mu$m hot bands, and a general spectral-fitting tool retrieves production rates and rotational temperatures for the trace volatiles; spaxel-by-spaxel fits show apparent $Q(\\mathrm{H_2O})$, rotational temperature, and ortho-to-para ratio all rising with nucleocentric distance. Third, a thermal dust model: radiative-equilibrium temperatures for porous grains of five compositions (amorphous carbon, amorphous olivine, amorphous pyroxene, crystalline olivine, crystalline pyroxene) are summed over a Hanner size distribution and fit to the 7 to 27 $\\mu$m spectral energy distribution, with model choice by an information criterion favoring the amorphous-olivine variant; a PAH emission library is then fit to the residual after subtracting scattered light, thermal dust, and molecular lines. The load-bearing step is the selection of the 5 $\\mu$m hot-band water rate as the global production rate.","core_discovery":"On the paper's own terms, the discovery is that C/2017 K2 (PanSTARRS) is a hyperactive comet with a small nucleus. Combining the water production rate $Q(\\mathrm{H_2O}) = 7.6\\times10^{28}\\,\\mathrm{s^{-1}}$ derived from NIRSpec 5 $\\mu$m hot-band lines with an upper-limit nucleus radius of 4.2 km from radial surface-brightness profiles, and dividing by the sublimation rate a bare exposed water-ice surface would supply at 2.35 au, the paper finds that the active water-ice area is at least 86% of the nucleus surface, far above the roughly 10% typical of most comets. The thermal modeling of the 7 to 27 $\\mu$m dust spectral energy distribution returns a coma of sub-micron grains dominated by Mg-rich crystalline olivine, with amorphous carbon, amorphous olivine, and amorphous pyroxene contributing the rest and a crystalline mass fraction $f_{\\rm cryst} = 0.384 \\pm 0.065$; the residual 3 to 8.6 $\\mu$m spectrum is fitted by fluorescing PAHs, with small heavily hydrogenated neutral molecules producing the 3.42 $\\mu$m feature and small cations producing the 6 to 9 $\\mu$m features. The paper also reports that the apparent water production rate increases with projected distance from the nucleus, evidence for an extended source of water released from sublimating icy grains, which is the mechanism invoked to explain the hyperactivity.","pith_inferences":["If the lower 6.3 $\\mu$m band rates (roughly 1 to 2.6$\\times10^{28}$ s$^{-1}$) rather than the 5 $\\mu$m hot-band rate turn out to be the true global water output, the active fraction drops to roughly 10 to 30% and the hyperactivity headline result disappears; the two-band discrepancy is therefore the single most decisive open question this paper leaves.","The rise of apparent $Q(\\mathrm{H_2O})$ with nucleocentric distance implies that the largest-beam water measurements should keep climbing, a prediction already gestured at by the radio OH value the paper quotes; comparing a large-beam OH measurement with the JWST apertures is a straightforward test.","The fitted PAH population is hostage to the spectral library: the paper notes that the next release of the PAH database, with edge-defect spectra, could change the species mix, so re-fitting the same residuals against that library is a cheap, decisive check on whether small hydrogenated neutrals truly dominate the 3.42 $\\mu$m emission.","The 14 $\\mu$m residual, tentatively attributed to CAI-like aluminum- and titanium-oxide minerals, could be tested by stacking JWST spectra of the several Spitzer-era comets that show the same residual feature to see whether its position and shape match perovskite or spinel resonances."],"forward_implications":["C/2017 K2 joins the small set of hyperactive comets, so any model of its behavior must include a distributed source of water from icy grains in the coma rather than sublimation from the nucleus surface alone.","The high crystalline mass fraction ($f_{\\rm cryst} \\simeq 0.384 \\pm 0.065$) in a dynamically old Oort Cloud comet becomes a datum for how much crystalline material survives in the outer solar system, bearing on radial-mixing scenarios in the protoplanetary disk.","The PAH interpretation gives JWST comet spectroscopy a direct link to the organic molecules measured by mass spectrometry in comet 67P and in returned asteroid samples, extending the sample of cometary organic matter to a long-period Oort Cloud object.","The distinct spatial distributions of water-driven versus CO$_2$-driven volatiles imply separate ice phases in the nucleus, reinforcing the picture from comet 67P that H$_2$O and CO$_2$ ices are not intimately mixed.","The measured $^{12}$CO$_2$/$^{13}$CO$_2$ ratio, consistent with the terrestrial $^{12}$C/$^{13}$C of 89, adds a comet to the small set with a carbon isotope ratio determined from space-based spectroscopy.","C/2017 K2 joins the small set of hyperactive comets, so any model of its behavior must include a distributed source of water from icy grains in the coma rather than sublimation from the nucleus surface alone.","The high crystalline mass fraction ($f_{\\rm cryst} \\simeq 0.384 \\pm 0.065$) in a dynamically old Oort Cloud comet becomes a datum for how much crystalline material survives in the outer solar system, bearing on radial-mixing scenarios in the protoplanetary disk.","The PAH interpretation gives JWST comet spectroscopy a direct link to the organic molecules measured by mass spectrometry in comet 67P and in returned asteroid samples, extending the sample of cometary organic matter to a long-period Oort Cloud object."],"supporting_citations":[{"why":"Supplies the ice-sublimation model that converts the water production rate and nucleus size into the active-area and active-fraction values underlying the hyperactivity claim.","marker":"Cowan & A'Hearn 1979"},{"why":"Provides the thermal model used to translate the 5 to 7 $\\mu$m continuum into the nucleus radius upper limits (3.7 to 6.0 km depending on beaming parameter).","marker":"Harris 1998"},{"why":"Supplies the fluorescence fitting tool that retrieves molecular production rates and rotational temperatures, including the 5 $\\mu$m hot-band water rate that drives the hyperactivity result.","marker":"Villanueva et al. 2018"},{"why":"Provides the H$_2$O fluorescence model used to fit the 6.3 $\\mu$m $\\nu_2$ band spectra, yielding the lower water rates that define the band discrepancy.","marker":"Crovisier 2009"},{"why":"Supplies the thermal dust emission model, the grain optical constants and porosity prescription, and the Spitzer comet comparison sample against which the crystalline mass fraction is judged.","marker":"Harker et al. 2023"},{"why":"Ground-based IRTF study of the same comet whose water production rate is about a factor of two lower than the NIRSpec hot-band value, framing the unexplained discrepancy.","marker":"Ejeta et al. 2025"},{"why":"Defines the grain size distribution used in the dust thermal modeling.","marker":"Hanner et al. 1994"},{"why":"Provides the interpretation of heavily hydrogenated PAHs and the 3.4 $\\mu$m emission feature used in the PAH model.","marker":"Sandford et al. 2013"},{"why":"Supplies the PAH spectral database and fitting suite used to identify the emitting species in the 3 to 8.6 $\\mu$m residual.","marker":"Boersma et al. 2014"}],"fun_headline_variants":["Hyperactive K2: tiny nucleus, ≥86% surface ice active","JWST reveals comet K2's 86% active ice area on a <4.2 km nucleus","K2's coma: crystalline olivine dust and PAHs from a tiny nucleus","Comet K2's hyperactivity tied to sublimating icy grains","JWST spots PAHs and crystalline dust in comet K2's coma"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The hyperactivity result rests entirely on taking the 5 $\\mu$m hot-band water production rate of $7.6\\times10^{28}$ s$^{-1}$ as the comet's global water output, while the paper's own fits to the 6.3 $\\mu$m band give rates roughly two to eight times lower and the paper states that the discrepancy is not explained.","fun_headline_variants_meta":{"raw":{"variants":["Hyperactive K2: tiny nucleus, ≥86% surface ice active","JWST reveals comet K2's 86% active ice area on a <4.2 km nucleus","K2's coma: crystalline olivine dust and PAHs from a tiny nucleus","Comet K2's hyperactivity tied to sublimating icy grains","JWST spots PAHs and crystalline dust in comet K2's coma"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001181,"raw_usage":{"total_tokens":5025,"prompt_tokens":1241,"completion_tokens":3784,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":857,"completion_tokens_details":{"reasoning_tokens":3680}},"tokens_in":857,"tokens_out":3784,"duration_ms":26273,"temperature":1.0,"reasoning_tokens":3680,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-16T05:43:06.787529+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A radiative-transfer calculation of the optically thick H$_2$O 6.3 $\\mu$m $\\nu_2$ band along the actual JWST lines of sight, using opacity-corrected excitation models, would decide the matter: if the corrected 6.3 $\\mu$m rate stays near 1 to 2.6$\\times10^{28}$ s$^{-1}$ rather than converging to $7.6\\times10^{28}$ s$^{-1}$, the active fraction falls to roughly 10 to 30% and the hyperactivity claim is refuted. A second, independent check is a new JWST observation of the comet at a different heliocentric distance to see whether the hot-band-to-$\\nu_2$ ratio persists or whether the discrepancy was an aperture or opacity artifact.","supporting_citations":[],"review_version":1}