{"id":"70b74275-117d-475c-a6b0-e393e2790422","arxiv_id":"2603.21670","paper_version":2,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":5,"one_line_summary":"In 83 resolved hot molecular cores, protostellar luminosities derived from temperature and density profiles yield Jeans masses that systematically exceed envelope masses, evidencing thermal suppression of fragmentation.","lead":"ALMA observations of 83 hot molecular cores show that heat from embedded massive protostars raises the local Jeans mass above the core mass, suppressing further fragmentation. This supplies large-sample observational support for the long-standing simulation prediction that thermal feedback helps form massive stars.","discovery_kind":"extension","skeptic_critique":{"model":"grok-4.5","headline":"MJeans > Menv is partly circular: both sides are built from the same CH3CN Trot field, so the decisive mass comparison is not an independent test of thermal feedback.","rationale":"The Reader correctly isolates Tdust ≈ Trot as the weakest assumption and correctly flags that it feeds both Menv and the temperature used for MJeans/L⋆. I sharpen the same point: the decisive comparison MJeans > Menv is not an independent observational test of feedback because both quantities are constructed from the identical Trot field; a systematic COM–dust temperature offset moves the two masses in opposite directions and can manufacture the reported factor-of-two excess. The L⋆–MJeans correlation is similarly non-independent. The paper already notes the Motte et al. discrepancy and the spherical-symmetry caveat, so the concern is not new, but it is load-bearing for the strongest claim and has not been quantified. A simple f-scaling of Tdust through the existing maps would settle whether the result survives. That leaves the verdict at CONDITIONAL (same as the Reader), with high confidence that the work is valuable once the temperature dependence is shown explicitly. No stronger rejection is warranted: the sample size, profile fitting, and projection test are carefully done, and the empirical L⋆–core relations remain useful even if the Jeans comparison is tempered.","tokens_in":46699,"tokens_out":704,"duration_ms":7757,"concrete_test":"Recompute NH2 (hence Menv and ⟨n⟩) and MJeans for the full sample after rescaling Tdust = f × Trot with f in {0.5, 0.7, 1.0} (motivated by the Motte et al. COM-vs-dust offset). Report the fraction of cores with MJeans > Menv and the mean MJeans/Menv ratio at each f. If the mean ratio falls below ~1 for f ≲ 0.7, the headline claim is temperature-assumption dependent and should be qualified.","verdict_should_be":"CONDITIONAL","load_bearing_attack":"The central claim is that MJeans exceeds Menv (average factor ~2), providing observational evidence that thermal feedback suppresses HMC fragmentation (§4.2, Abstract). MJeans is computed from Eq. 8 with T = ⟨T⟩_M (mass-averaged CH3CN Trot) and n = core-averaged volume density from the Plummer fit to NH2. Menv is obtained by integrating the same NH2 map, and NH2 itself is derived from the 1.3 mm continuum under Tdust = Trot (§3.1, Eq. 3). Thus both the numerator (T^{3/2}) and the denominator of MJeans, as well as Menv, inherit the same temperature field. If COM-traced gas is systematically hotter than the dust that dominates the continuum (as the authors note Motte et al. 2025 find, and as they flag in §4.4), then Menv is underestimated while MJeans is overestimated, artificially widening the gap. The L⋆–MJeans correlation is likewise non-independent because L⋆ is fitted by matching RADMC-3D to the same Tobs profile. The paper’s own caveats acknowledge the Tdust = Trot risk but do not quantify how large a T offset would reverse MJeans ≳ Menv.","agreement_with_reader":"agree"},"referee_report":{"model":"grok-4.5","summary":"The paper presents a homogeneous ALMA-QUARKS analysis of 83 spatially resolved hot molecular cores. Using multi-K CH3CN (12–11) fits with spectuner and 1.3 mm continuum (with H30α free–free subtraction where detected), the authors derive radial temperature, Plummer-like density, and broken power-law CH3CN abundance profiles. Embedded protostellar luminosities L⋆ are obtained by χ²-matching RADMC-3D envelope temperature profiles to the observed T(r). They report empirical L⋆–Menv, L⋆–a, and L⋆–nc relations, a positive L⋆–MJeans correlation, and that thermal Jeans masses systematically exceed envelope masses (average factor ~2). From this they argue that protostellar thermal feedback can suppress further HMC fragmentation and that more massive clumps host more luminous protostars, strengthening feedback-driven coevolution.","tokens_in":47035,"tokens_out":1757,"duration_ms":38360,"significance":"If the MJeans ≳ Menv result and the associated L⋆–MJeans and L⋆–Mclump trends hold under independent temperature and mass constraints, this would be one of the strongest observational supports to date for radiative suppression of core fragmentation in massive star formation, on a sample far larger and more uniform than prior case studies. The empirical core-scale L⋆–Menv, L⋆–a, and L⋆–nc relations are useful model constraints regardless. Strengths include the large resolved sample, automated multi-transition fitting, free–free handling, projection-corrected RT tests (Δlog L⋆ ≲ 0.1), distance-limited correlation checks, and an explicit caveats section. The main interpretive load rests on whether the Jeans comparison is sufficiently independent of the shared temperature field used to build both sides.","major_comments":[{"comment":"§4.2 and Abstract (central claim): MJeans is computed from Eq. (8) with T = ⟨T⟩_M (mass-averaged CH3CN Trot) and n from the Plummer fit to NH2, while Menv is the integral of the same NH2 map. NH2 itself is derived from continuum under Tdust = Trot (Eq. 3, §3.1). Thus both the T^{3/2} boost in MJeans and the continuum mass scale inherit the same temperature field: higher adopted T raises MJeans and lowers Menv, widening the gap by construction. The claim that average MJeans is ~2× average Menv is therefore not an independent test of thermal feedback until the authors quantify how large a systematic Tdust < Trot offset (as they cite from Motte et al. 2025 and flag in §4.4) would reverse MJeans ≳ Menv for the bulk of the sample. A simple sensitivity grid (e.g., Tdust = f Trot with f = 0.5–1.0, recomputing NH2, Menv, and optionally L⋆) is needed before the fragmentation-suppression conclusio","section":null},{"comment":"§4.2 and §3.3.3: The reported strong L⋆–MJeans correlation (rp = 0.75; Log[MJeans] = 0.32 Log[L⋆] − 0.63) is partly expected because L⋆ is optimized so that RADMC-3D matches the same observed temperature profile that enters ⟨T⟩_M in Eq. (8). Density structure also depends on T via NH2. The paper should either (i) demonstrate residual correlation after removing the direct T-driven component (e.g., partial correlation controlling for ⟨T⟩_M, or MJeans computed with a fixed reference T), or (ii) clearly reframe the result as a consistency check that the measured (T,n) structures imply Jeans-stable envelopes at the luminosities required by RT, rather than as independent evidence that feedback raises Jeans mass. Without that, the Abstract wording overstates the independence of the test.","section":null},{"comment":"§3.1, §3.3.3, and §4.4: The assumption Tdust ≈ Tkin ≈ Trot is used both to convert continuum to NH2/Menv and as the observational target for the L⋆ fit. The caveats correctly note that COM-traced gas may be hotter than the dust dominating the continuum, which would bias L⋆ high and Menv low. Because this dual use is load-bearing for every mass–luminosity and Jeans comparison in the paper, the main text (not only §4.4) should state the direction and approximate magnitude of the bias and show that the key empirical slopes (especially Log[Menv] = 1.01 Log[L⋆] − 4.80 and the MJeans > Menv census) remain qualitatively intact under a plausible T offset. If they do not, the conclusions must be softened accordingly.","section":null}],"minor_comments":[{"comment":"Abstract and §4.2: Clarify whether “average MJeans being two times larger than the average Menv” is the ratio of means, the mean of ratios, or the median ratio; these differ when the scatter in Fig. 8 is large.","section":null},{"comment":"§3.3.1: The text notes that the projected power-law fit underestimates q by ~0.15 (Estalella et al. 2024) but still reports uncorrected q for comparison. Consider also tabulating a simple deprojected or RT-consistent q so readers do not mix projected and physical indices.","section":null},{"comment":"§3.2 / Table E1: Dust-ff cores are defined by H30α > 3σ at the continuum peak; the text correctly notes non-detections do not imply zero free–free. A short estimate of residual free–free contamination for non-detections (or an upper limit on mass bias) would strengthen the continuum mass scale.","section":null},{"comment":"Figure 4 caption: Exclusion of I16348-4654-HC1 and I18056-1952-HC1 from the mean T profile is appropriate; state whether they remain in the MJeans/Menv and correlation statistics (they appear extreme in Table E1).","section":null},{"comment":"§3.3.3: ZAMS mass–luminosity conversion is mentioned only briefly; given that L⋆ includes accretion, avoid implying those masses are true stellar masses without a short caveat near the quoted 6–114 M⊙ range.","section":null},{"comment":"Typos / wording: “obsereved” (§2); “F eedback” in the title line of the draft header; “pow-law” in Appendix E column description; “aknowledges” in acknowledgments. Standardize CH3CN vs \\ch3cn{} and Log vs log notation.","section":null},{"comment":"§4.3: The coevolution discussion (L⋆ ∝ Mclump^1.22 and comparison to m_max–M_cluster) is interesting but partly statistical (as §4.4 notes). Soften causal language (“preferentially host,” “leading to stronger thermal feedback”) where only correlation is shown.","section":null},{"comment":"Appendix B: Several quantities correlate with distance (L⋆, Menv, FWHM, rb). The distance-limited rp values in Table D1 help; consider marking in Fig. 7/8 which points lie beyond 5 kpc so readers can visually assess leverage.","section":null}],"recommendation":"major_revision","confidential_remarks":"The observational product (83 resolved T/n/X profiles and L⋆ estimates) is valuable and likely publishable even if the fragmentation-suppression claim is toned down. The main risk is overclaiming independence of MJeans vs Menv. I would accept after the authors either quantify the Tdust offset and circularity or reframe §4.2/Abstract as a consistency argument rather than decisive evidence. Scope fits a major star-formation journal; no integrity concerns."},"author_rebuttal":null,"desk_editor":{"model":"grok-4.5","letter":"The real advance here is the catalog: 83 QUARKS hot cores with uniform CH3CN multi-K temperatures, Plummer density fits, broken-power-law abundances, and RADMC-3D luminosities. That scale and homogeneity is new; prior work (Gieser, Palau, Motte) was smaller or heterogeneous. The empirical relations—Log Menv = 1.01 Log L⋆ − 4.80, Log a = 0.46 Log L⋆ + 0.52, Log nc = −0.55 Log L⋆ + 10.47—are clean and will be cited by modelers. L⋆ tracks clump bolometric luminosity within ~1 dex and correlates with clump mass, which is a useful observational anchor for coevolution arguments.\n\nMethods are careful. Spectuner multi-K fitting, H30α free-free subtraction for the 11 dust-ff cores, projection-corrected RADMC-3D (Δlog L⋆ ≲ 0.1), and a distance-limited check that preserves most correlations all look solid. The abundance chemistry appendix is a nice extra. Citation pattern is appropriate; they engage the simulation literature and the observational caveats (Motte et al. 2025 on Tdust vs Trot, Estalella projection bias) rather than ignoring them.\n\nThe soft spot is real but not fatal. MJeans uses mass-averaged Trot and volume-averaged n from the same maps that give Menv (via Tdust = Trot in the continuum conversion). So both sides of MJeans ≳ Menv inherit the temperature field; if COM gas is systematically hotter than the dust continuum, the gap widens artificially. The L⋆–MJeans correlation is likewise non-independent because L⋆ is fitted to the same Tobs. The authors flag this in §4.4 and do not over-claim a pure independent test. The average factor-of-two excess still holds under their assumptions and is consistent with the simulation prediction they set out to test. Spherical symmetry and single-band opacity are standard limitations, not unique to this paper.\n\nThis is for people working on massive-star formation, thermal feedback, and IMF regulation. It deserves a serious referee. I would cite the relations and the sample; I would treat the fragmentation-suppression claim as supportive evidence, not the last word, until multi-band dust temperatures exist. Send it to peer review.","headline":"Large homogeneous HMC sample with useful L⋆–core relations; MJeans>Menv is real under stated assumptions but partly shares the same Trot field, so the feedback claim is supportive rather than decisive.","tokens_in":47851,"tokens_out":594,"would_cite":true,"duration_ms":8063,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"grok-4.5","headline":"Thermal feedback from massive protostars raises the local Jeans mass above the envelope mass, suppressing further fragmentation of hot molecular cores.","keywords":["hot molecular cores","thermal feedback","Jeans mass","massive star formation","protostellar luminosity","CH3CN temperature profiles","ALMA QUARKS","fragmentation suppression"],"falsifier":"Multi-band continuum maps at matched high resolution that yield dust temperatures systematically lower than the CH3CN rotational temperatures would lower both derived luminosities and Jeans masses enough that M_Jeans no longer exceeds M_env for most of the sample.","tokens_in":47570,"feed_emoji":"☀️","tokens_out":884,"duration_ms":9051,"temperature":0.7,"pith_summary":"Massive young stars heat their natal envelopes, and that heat is expected to change how the gas can fragment. This paper measures temperature and density structure in 83 spatially resolved hot molecular cores and uses those profiles to infer the luminosities of the embedded protostars. The key finding is that the thermal Jeans mass set by the heated gas systematically exceeds the measured envelope mass, by about a factor of two on average, and scales positively with protostellar luminosity. If that relation is real, radiative heating can stop cores from breaking into many smaller pieces and thereby favors the growth of massive stars. The same data also show that more massive parent clumps host more luminous protostars, so stronger heating and stronger suppression of fragmentation go together with larger mass reservoirs. The result supplies an observational counterpart to simulations that have long predicted this feedback pathway.","feed_headline":"Heated cores stop fragmenting: Jeans mass exceeds envelope mass","feed_subtitle":"In 83 hot cores, protostellar heating raises the local Jeans mass enough to favor massive stars","key_machinery":"Local thermal Jeans mass evaluated from the mass-averaged envelope temperature and the core-averaged volume density, compared against the continuum-derived envelope mass and against the protostellar luminosity recovered by fitting the observed density and temperature profiles with Monte-Carlo radiative transfer.","core_discovery":"In a sample of 83 resolved hot molecular cores, the thermal Jeans mass computed from the observed temperature and density structure exceeds the envelope mass, with average M_Jeans about twice average M_env, and M_Jeans rises with the luminosity of the embedded massive protostar. That is presented as direct observational evidence that thermal feedback suppresses further fragmentation of HMCs and thereby promotes massive star formation.","pith_inferences":["If the Jeans-mass excess is the main regulator, the high-mass end of the initial mass function should be set partly by how early and how strongly the first massive object heats its core, not only by the initial clump mass reservoir.","Distance-limited reanalysis already weakens the L★–nc anti-correlation, so future work that fixes physical scale (rather than angular scale) may revise which structural parameters truly track luminosity.","The reported L★ ∝ M_Jeans^3.1 relation is close to a stellar mass–luminosity track; testing whether final stellar mass tracks the local Jeans mass at the hot-core stage would link envelope heating directly to the stellar mass spectrum."],"forward_implications":["Empirical L★–Menv, L★–a, and L★–nc power laws become benchmarks that theoretical models of massive protostellar envelopes must reproduce.","Cores that remain above the local Jeans mass should show little further sub-fragmentation at higher resolution, favoring single massive objects or high-mass binaries over large low-mass clusters.","More massive clumps should preferentially form more luminous protostars and therefore experience stronger thermal suppression of fragmentation.","Radial CH3CN abundance breaks near ~1000–2000 au can be read as a chemical clock of how long different envelope layers have spent above ~100–200 K."],"fun_headline_variants":["Jeans mass tops envelope mass: thermal feedback curbs HMC fragments","Protostellar heat lifts Jeans mass above core mass in 83 HMCs","Massive stars suppress HMC fragmentation via rising Jeans mass","Luminous protostars heat cores until Jeans mass exceeds envelopes","Thermal feedback from protostars doubles average Jeans over env mass"],"cache_read_input_tokens":32896,"weakest_assumption_plain":"The dust temperature used for both column densities and luminosity fitting is taken equal to the gas temperature measured from CH3CN, under the assumption that dust and gas stay thermally locked in these dense regions.","fun_headline_variants_meta":{"raw":{"variants":["Jeans mass tops envelope mass: thermal feedback curbs HMC fragments","Protostellar heat lifts Jeans mass above core mass in 83 HMCs","Massive stars suppress HMC fragmentation via rising Jeans mass","Luminous protostars heat cores until Jeans mass exceeds envelopes","Thermal feedback from protostars doubles average Jeans over env mass"]},"model":"grok-4.5","effort":"low","cost_usd":0.00505,"raw_usage":{"total_tokens":1499,"prompt_tokens":938,"num_sources_used":0,"completion_tokens":95,"cost_in_usd_ticks":50500000,"prompt_tokens_details":{"text_tokens":938,"audio_tokens":0,"image_tokens":0,"cached_tokens":128},"completion_tokens_details":{"audio_tokens":0,"reasoning_tokens":466,"accepted_prediction_tokens":0,"rejected_prediction_tokens":0}},"tokens_in":938,"tokens_out":95,"duration_ms":4975,"temperature":1.0,"reasoning_tokens":466,"cache_read_input_tokens":128,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-07-13T20:39:26.198273+00:00","model_set":{"reader":"grok-4.5"},"falsifier":"Multi-band continuum maps at matched high resolution that yield dust temperatures systematically lower than the CH3CN rotational temperatures would lower both derived luminosities and Jeans masses enough that M_Jeans no longer exceeds M_env for most of the sample.","supporting_citations":[],"review_version":1}