{"id":"2dc55980-01ca-487c-8eaf-94e585198a00","arxiv_id":"2507.23413","paper_version":1,"verdict":"ACCEPT","confidence":"HIGH","novelty_score":6.0,"correctness_risk":"low","formal_verification":"none","parameter_count":2,"one_line_summary":"TOI-5795 b is a confirmed hot super-Neptune (M = 23.7 Earth masses, R = 5.6 Earth radii) orbiting a metal-poor G3 V star every 6.14 days.","lead":"Astronomers confirmed a planet candidate seen by TESS around a metal-poor, Sun-like star 162 parsecs away. TOI-5795 b is a hot super-Neptune on a 6.14-day orbit, giving planetary scientists a new test case for how such planets form and lose atmosphere.","discovery_kind":"extension","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The RV jitter caveat is the only fragile premise for the planet's mass, but it is adequately mitigated by activity diagnostics and phase coverage; no verdict change.","rationale":"The paper's central assertion is a standard exoplanet confirmation. The photometry (12 TESS transits plus two ground-based transits), high-resolution imaging, and RVs are mutually consistent and point to a transiting planet; the only place a false positive could enter silently is the RV mass. The reader and I converge on the white-noise/jitter assumption as the weakest link. I checked whether a correlated signal could plausibly be present: the host is inactive, the 6.14 d period is not a rotation harmonic, no activity indicator tracks the RV period, and the residual periodogram is empty. The RV phase coverage is good over the HARPS baseline, and the TRES data provide no evidence for a long-period trend. The reported mass significance is already marginalized over the fitted jitter. The formation simulations are not the central claim and are already phrased as suggestive rather than definitive. I therefore would keep the ACCEPT verdict and high confidence. The Table 2 log gp inconsistency (7.33 cgs vs ~2.87 cgs implied by Mp/Rp) is worth correcting but does not bear on the planet's existence or its measured mass and radius.","tokens_in":23491,"tokens_out":9697,"duration_ms":119588,"concrete_test":"Refit the HARPS RVs of Sect. 4.2 with a correlated-noise model (e.g., a celerite GP) and a linear trend term in place of the white-jitter assumption, then compare the posterior on K with the published 8.97+1.51-1.74 m/s; if K shifts by more than ~1.5 m/s, the mass claim needs revision, and if it does not, the concern is settled.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim requires Mp = 23.66 M_Earth, derived in Sect. 4.2 from a 1-Keplerian fit to 19 HARPS RVs with a fitted white jitter of 3.75+1.23-1.08 m/s on top of K = 8.97 m/s. If an unmodeled correlated signal at ~6.14 d, or an unmodeled long-period trend, were present, the inferred K could be biased. This is the weakest premise in the chain. I do not find it load-bearing: the star is quiet (log R'_HK = -5.07), rotation is slow (Prot > 30 d), all activity-indicator periodograms show FAP > 15%, the residual periodogram shows no significant signal, the 6.14 d phase is well covered over ~7 cycles, and the 13 TRES RVs spanning two years show no long-period trend. The quoted mass significance already accounts for the fitted jitter, and the authors explicitly flag the elevated jitter and recommend continued monitoring. The formation and evaporation conclusions are secondary and hedged. A minor internal typo appears in Table 2, where log gp = 7.33 cgs is inconsistent with the quoted Mp and Rp (which imply ~2.87 cgs); this does not affect the central claim.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports the confirmation and characterization of the transiting super-Neptune TOI-5795 b. Using 12 TESS transits from three sectors, two ground-based transits, and 19 HARPS radial velocities, the authors derive an orbital period of 6.1406 d, a mass of 23.66 M⊕, a radius of 5.62 R⊕, and a bulk density of 0.73 g cm^-3, orbiting a metal-poor G3 V star. High-resolution speckle and AO imaging exclude significant blends. The planet lies at the edge of the Neptune desert / beginning of the savanna in the period-radius diagram. The paper also presents Monte Carlo pebble-accretion formation simulations, which fail to reproduce the planet's mass and orbit in the vast majority of trials, and an atmospheric-evolution study suggesting that the planet has lost 4-9 M⊕ of its initial atmosphere.","tokens_in":23780,"tokens_out":11619,"duration_ms":117197,"significance":"If the characterization holds, TOI-5795 b is a valuable addition to the small sample of well-characterized hot super-Neptunes at the Neptune desert/savanna boundary. The precise mass and radius (both at the roughly 5-10% level) and the metal-poor host star make it an important test case for formation and evolution models. The paper's strengths include the multi-dataset joint analysis, explicit exclusion of blends with high-angular-resolution imaging, injection-recovery simulations for the RV detection sensitivity, and the use of independent formation simulations that yield a genuine negative result for pebble accretion. The atmospheric-evolution analysis is clearly hedged against the large uncertainty in the star's high-energy history. The TSM of ~100 also makes this a promising target for future atmospheric follow-up.","major_comments":[],"minor_comments":[{"comment":"The value log gp = 7.33±1.29 cgs in Table 2 is inconsistent with the quoted Mp = 23.66 M⊕ and Rp = 5.62 R⊕, which imply log gp ≈ 2.87 cgs; please correct this typographical error.","section":"Table 2"},{"comment":"The text reports 'e = 0.15±0.06' and states that the eccentricity is compatible with zero at 95.5% confidence, while Table 2 gives a 2σ upper limit of e < 0.25; these statements should be reconciled, for example by quoting the median and 68% credible interval together with the upper limit and noting that the posterior is non-Gaussian.","section":"Sect. 4.2"},{"comment":"The abstract describes TOI-5795 b as 'at the edge of the Neptune desert', but the paper adopts the Castro-González et al. (2024a) definitions in which the desert is P_orb < 3.2 d, the ridge is 3.2–5.7 d, and the savanna is 5.7–100 d; with P_orb = 6.14 d the planet is actually at the beginning of the savanna, so the wording should be aligned.","section":"Abstract and Sect. 7"},{"comment":"The column 'δ(J2010)' should read 'δ(J2000)'.","section":"Table 1"},{"comment":"The TRES RVs are described as having an average precision of 27.7 m/s, but the listed values show a scatter of about ±50 m/s; reporting the RMS of the TRES RVs would help the reader gauge the sensitivity to long-period companions.","section":"Sect. 2.4.1"},{"comment":"Given that the fitted jitter (3.75 m/s) is a sizable fraction of the RV semi-amplitude (8.97 m/s), it would be informative to state explicitly the resulting detection significance of the Keplerian signal after the jitter is included, beyond the >5σ claim, and to note whether a model with a correlated noise component changes the inferred mass.","section":"Sect. 4.2"}],"recommendation":"minor_revision","confidential_remarks":"This is a straightforward, well-executed confirmation paper. The main scientific result is solid; the only issues are presentation-level. The log gp typo in Table 2 should be caught in proof. The paper is a good fit for A&A. No concerns about novelty or citation practices."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"You should know one thing about this paper: the planet is real and the mass is believable, but the real value is that it adds a well-characterized data point at the ridge/savanna boundary, not a new mechanism or measurement capability.\n\nWhat is genuinely new: TOI-5795 b gets its first confirmation and mass measurement. The host is a metal-poor, old G3 star, which matters for the demographic question about Neptune-desert versus savanna hosts. The data are solid: 12 TESS transits, two ground-based transits, 19 HARPS RVs, 13 TRES RVs spanning two years, and high-resolution imaging that rules out blends. The RV signal is >5 sigma, the star is quiet, and the analysis is standard and readable. Credit where earned: the formation simulations with GroMiT are independent of the observed planet and give a genuine negative result, so the \"pebble accretion struggles here\" conclusion is an honest, limited negative result rather than a circular one. The atmospheric evolution section is appropriately hedged.\n\nThe soft spots are minor. The RV jitter at 3.75 m/s against K=8.97 m/s with 19 points is the weakest premise, but the activity indicators, phase coverage, and lack of a long-term trend make the mass robust. Eccentricity is only bounded to <0.25, and the evaporation numbers depend heavily on assumed XUV tracks, but the authors say so. One real typo: Table 2 lists log gp = 7.33 cgs, which is inconsistent with the quoted Mp and Rp (that would be ~2.87 cgs). It does not affect anything, but it should be fixed before publication. None of these are load-bearing.\n\nWho gets value from this: people working on Neptune desert/savanna demographics, formation modelers looking for tension cases, and anyone compiling atmospheric follow-up targets—TSM ~ 100 is genuinely worth having. The paper is not a breakthrough, but it is clean and useful.\n\nRecommendation: send it to serious peer review. It deserves a proper referee, and with the typo fixed and modest tightening of the caveats, it should be accepted.","headline":"A solid super-Neptune confirmation with honest analysis; the RV jitter is the only fragile premise and it holds up.","tokens_in":24439,"tokens_out":1467,"would_cite":true,"duration_ms":18040,"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":"TOI-5795 b is a confirmed hot super-Neptune: a 23.66-Earth-mass, 5.62-Earth-radius planet on a 6.14-day, near-circular orbit at the edge of the Neptune desert.","keywords":["planetary systems","techniques: radial velocities","techniques: photometry","stars: individual: TOI-5795","hot super-Neptune","Neptune desert","TESS","atmospheric evaporation"],"falsifier":"A new radial-velocity campaign of roughly 30 additional HARPS measurements spread over at least one full year would settle the mass. If a statistically significant periodicity or trend remains after fitting the single Keplerian, and removing it shifts the best-fit semi-amplitude by more than about $1.5$ m s$^{-1}$, the quoted mass and its claimed significance would need revision.","tokens_in":23353,"feed_emoji":"🪐","tokens_out":15405,"duration_ms":146132,"temperature":0.7,"pith_summary":"This paper confirms and characterizes TOI-5795 b, a planet discovered in TESS photometry around the metal-poor G3 star TOI-5795. Combining 19 HARPS radial-velocity measurements with three sectors of TESS light curves and two ground-based transits, the authors measure a planet mass of $M_p = 23.66^{+4.09}_{-4.60}\\ M_\\oplus$ and a radius of $R_p = 5.62 \\pm 0.11\\ R_\\oplus$, placing it on a 6.14-day, near-circular orbit at the edge of the Neptune desert. The authors argue that the planet's low density and its host's low metallicity align it with the 'savanna' population rather than with the metal-rich hosts of desert planets, supporting a distinct formation origin. Their pebble-accretion simulations almost never reproduce this planet, and their atmospheric-evolution models indicate it lost 4–9 $M_\\oplus$, roughly 14–27% of its initial mass, to photoevaporation while contracting from an initial radius near 10.5–11.2 $R_\\oplus$. A well-characterized object like this is a test case for how close-in Neptunes form and evolve.","feed_headline":"Hot super-Neptune found at the edge of the Neptune desert","feed_subtitle":"Its 6.14-day orbit, low density, and metal-poor host resist standard pebble-accretion formation models.","key_machinery":"The argument is carried by the joint photometry+radial-velocity model, which fits the TESS and ground-based transit light curves together with the 19 HARPS velocities using a nested-sampling Bayesian approach; the HARPS data supply a Keplerian semi-amplitude of $K = 8.97^{+1.51}_{-1.74}$ m s$^{-1}$, from which the planet's mass follows. High-angular-resolution SOAR speckle and Palomar adaptive-optics imaging, reaching contrasts of roughly 3.9 and 7.5 magnitudes within 0.5 arcseconds, exclude contaminating companions that could dilute the transit. Two modeling tools interpret the result: the GroMiT Monte Carlo code, a pebble-accretion growth-and-migration simulator whose synthetic populations only rarely land on the observed mass and orbit, and an atmospheric-evolution code that uses the ATES mass-loss rates, driven by stellar XUV evolutionary tracks, to reconstruct the planet's earlier, larger state.","core_discovery":"TOI-5795 b is a genuine hot super-Neptune: a transiting planet with $M_p = 23.66^{+4.09}_{-4.60}\\ M_\\oplus$, $R_p = 5.62 \\pm 0.11\\ R_\\oplus$, bulk density $0.73 \\pm 0.13$ g cm$^{-3}$, and equilibrium temperature $1136 \\pm 18$ K, orbiting a $10.2^{+2.5}_{-3.3}$-Gyr-old, metal-poor ($[\\mathrm{Fe/H}] = -0.27 \\pm 0.07$) G3 V star every $6.1406325 \\pm 0.0000054$ days on an orbit compatible with circular. The detection rests on a joint fit of TESS and ground-based photometry with HARPS radial velocities, and high-angular-resolution speckle and adaptive-optics imaging excludes blended eclipsing binaries as the source of the signal. The paper further claims that standard pebble-accretion formation models fail to produce this planet (one match in $4 \\times 10^5$ simulations under the native disk, and one more across alternative disk configurations), and that its atmosphere has been stripped and compressed over roughly 10 Gyr, with an inferred mass loss of 4–9 $M_\\oplus$ and a contraction from radii near 10.5–11.2 $R_\\oplus$ at 10 Myr to its current size. With a transmission spectroscopy metric near 100, the authors present it as a promising target for atmospheric follow-up.","pith_inferences":["Editorial: The elevated radial-velocity jitter ($3.75$ m s$^{-1}$, roughly 40% of the planet's semi-amplitude) is itself a clue; an outer companion revealed by a longer baseline would supply the natural trigger for the dynamical scattering the authors invoke.","Editorial: The evaporation models imply that at 10 Myr the planet had a radius near 10.5–11.2 $R_\\oplus$ and a mass of about 28–33 $M_\\oplus$; a survey of young clusters might catch such inflated progenitors and test this mass-loss history directly.","Editorial: Because the host is metal-poor and roughly 10 Gyr old, this system cleanly separates the two main desert-shaping mechanisms (photoevaporation versus top-down stripping); the planet's survival at 1136 K favors evaporation-and-migration models over primordial gas-giant stripping.","Editorial: Re-running the same planetary seeds with a high-eccentricity migration prescription added to the GroMiT pebble-accretion tracks, rather than smooth inward migration, is a direct computational test of the authors' post-formation-shaping hypothesis."],"forward_implications":["TOI-5795 b joins the small sample of well-characterized planets at the desert–savanna boundary; if the measured mass and radius hold, it becomes one of the few benchmarks for testing that boundary's physical origin.","The planet's low density and the host's low metallicity reinforce the demographic case that savanna Neptunes are not stripped gas giants, since the top-down pathway predicts metal-rich hosts.","The near-total failure of the pebble-accretion simulations implies that close-in super-Neptunes around 20–30 $M_\\oplus$ require either a different accretion mode, a more efficient migration channel, or a stochastic dynamical origin such as mergers or high-eccentricity tidal migration.","With a transmission spectroscopy metric near 100 and a bright host, the planet is a viable target for atmospheric spectroscopy; measuring its atmospheric metallicity would test whether the envelope is primordial or was accreted after a dynamical rearrangement."],"supporting_citations":[{"why":"Defines the joint photometric+RV modeling procedure and prior choices adopted for the global fit.","marker":"Naponiello et al. 2022"},{"why":"Provides the desert/ridge/savanna boundaries used to place TOI-5795 b at the edge of the Neptune desert.","marker":"Castro-González et al. 2024a"},{"why":"Supplies the host-star metallicity demographics used to assign TOI-5795 b to the savanna population.","marker":"Vissapragada & Behmard 2025"},{"why":"The GroMiT Monte Carlo code used for the planet-formation simulations.","marker":"Polychroni et al. 2023"},{"why":"Provides the pebble-accretion growth and migration model used by GroMiT.","marker":"Johansen et al. 2019"},{"why":"Provides the pebble isolation mass scaling law used in the simulations.","marker":"Bitsch et al. 2018"},{"why":"The atmospheric-evolution code used to reconstruct the planet's evaporation history.","marker":"Locci et al. 2019"},{"why":"The ATES approximation used to compute mass-loss rates in the evaporation modeling.","marker":"Caldiroli et al. 2021"},{"why":"Defines the transmission spectroscopy metric on which the paper's atmospheric-follow-up claim is based.","marker":"Kempton et al. 2018"},{"why":"The SOAR speckle observing program that produced the high-resolution imaging excluding contaminating sources.","marker":"Ziegler et al. 2020"}],"fun_headline_variants":["Hot super-Neptune at Neptune desert edge resists formation models","Metal-poor star hosts hot super-Neptune that defies formation","Neptune desert edge yields hot super-Neptune that evades standard models","Hot super-Neptune around metal-poor star puzzles planet-formation theory"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"That the scatter left over after subtracting the planet's signal from the 19 radial-velocity measurements is genuine white noise, so the fitted jitter of $3.75$ m s$^{-1}$ does not conceal a second signal that would change the measured mass.","fun_headline_variants_meta":{"raw":{"variants":["Hot super-Neptune at Neptune desert edge resists formation models","Metal-poor star hosts hot super-Neptune that defies formation","Neptune desert edge yields hot super-Neptune that evades standard models","Hot super-Neptune around metal-poor star puzzles planet-formation theory"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000998,"raw_usage":{"total_tokens":4403,"prompt_tokens":1302,"completion_tokens":3101,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":918,"completion_tokens_details":{"reasoning_tokens":3021}},"tokens_in":918,"tokens_out":3101,"duration_ms":26973,"temperature":1.0,"reasoning_tokens":3021,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T10:50:53.775748+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A new radial-velocity campaign of roughly 30 additional HARPS measurements spread over at least one full year would settle the mass. If a statistically significant periodicity or trend remains after fitting the single Keplerian, and removing it shifts the best-fit semi-amplitude by more than about $1.5$ m s$^{-1}$, the quoted mass and its claimed significance would need revision.","supporting_citations":[{"cited_title":"2022, , 667, A8","cited_arxiv_id":null,"evidence_quote":"Defines the joint photometric+RV modeling procedure and prior choices adopted for the global fit."},{"cited_title":"2023, GroMiT: Planet Growth and Migration Track code","cited_arxiv_id":null,"evidence_quote":"The GroMiT Monte Carlo code used for the planet-formation simulations."},{"cited_title":"2019, Astronomy & Astrophysics, 622, A202","cited_arxiv_id":null,"evidence_quote":"Provides the pebble-accretion growth and migration model used by GroMiT."},{"cited_title":"2019, , 624, A101","cited_arxiv_id":null,"evidence_quote":"The atmospheric-evolution code used to reconstruct the planet's evaporation history."},{"cited_title":"2020, , 159, 19","cited_arxiv_id":null,"evidence_quote":"The SOAR speckle observing program that produced the high-resolution imaging excluding contaminating sources."}],"review_version":1}