{"id":"37707d15-60bb-46c6-8471-22c8d5311c0e","arxiv_id":"2411.17640","paper_version":2,"verdict":"CONDITIONAL","confidence":"MODERATE","novelty_score":5.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":1,"one_line_summary":"An alias search of TESS long-period planet candidates confirms nine periods above 100 days, identifies five likely long-period planets, and corrects or refines periods for fourteen more.","lead":"This paper checks the reported orbital periods of 266 long-period planet candidates from NASA's TESS telescope and finds that many are actually shorter-period planets seen at the wrong interval. It confirms nine genuinely long-period planets, corrects several periods, and flags three candidate systems with timing variations, giving follow-up observers a cleaner list of cool planets.","discovery_kind":"new_application","skeptic_critique":{"model":"deepseek-v4-flash","headline":"Transit-search incompleteness leaves shorter-period aliases unruled out for the 'confirmed' long-period TOIs: the algorithm misses about one third of known transits and roughly 10% even above its own S=0.135 threshold.","rationale":"I read the paper in good faith as a catalog-refinement study. Its central claim is modest and useful: nine TOIs have periods genuinely longer than 100 days, with five more likely long-period, while many other long-reported TOIs are aliases. The code and data are public, and the paper is unusually transparent about its own detection limits, stating in Section 2.4 that roughly one third of known transits were missed and that the recovery rate at the adopted threshold is only 70%. That transparency is a credit to the authors, but it directly exposes the load-bearing assumption: an alias transit that is shallow, noisy, or poorly sampled can be missed, so 'no transit found at any alias' does not equal 'all shorter aliases are ruled out.' The reader's weakest-assumption analysis identifies exactly this point, and I agree with it. Because the concern is precisely what a conditional verdict should be conditioned on, and because the paper's stated sensitivity limits are already acknowledged, I do not see a reason to move the verdict to reject or accept: the conditional status correctly reflects that the nine confirmations need per-target completeness verification or follow-up data before being treated as secure.","tokens_in":10134,"tokens_out":4586,"duration_ms":44460,"concrete_test":"Run an injection-recovery experiment using the public exo-finder code on the actual TESS light curves of the nine confirmed TOIs in Table 3. Inject boxcar transits at each alias epoch (for example P_rep/n for n = 2..20 and the Farey nodes used in Section 2.2), spanning depths and durations that give S = 0.05-0.30, and measure the recovery fraction as a function of S and alias. If any injected shorter-period transit with S at or above 0.135 is recovered less than about 95% of the time for a candidate counted as confirmed, then the paper's claim that all shorter-period aliases are ruled out is not supported, and those entries should be demoted to 'likely long period' pending additional data.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The nine 'confirmed' long-period claims in Section 3.3 rest on the assertion that all shorter-period aliases are ruled out. That assertion depends entirely on the completeness of the transit search, and the paper's own sensitivity test in Section 2.4 shows the search is not complete. The algorithm identified 1530 of the known transits for the 266 long-period TOIs and missed 788; at the adopted signal threshold S = depth x duration ~ 0.135 the detection rate is only 70%, and even above that limit it is about 90%, not 100%. Therefore, for a candidate where no transit is found at an alias, the correct conclusion is 'no transit detected above the algorithm's completeness floor,' not 'no transit exists.' A real shorter-period companion with a somewhat shallower or noisier transit could be missed, especially if the alias falls in a noisy sector or a data gap. Table entries such as 'Missing Aliases: None' only state that the queried epochs had data, not that a transit there would have been recovered. The paper is honest about this limitation for the five 'Low signal!' cases and for TOI-1894's missing 1/2 alias, but the nine claimed confirmations (seven 'very clear' plus TOI-4633 and TOI-1894) are not backed by a per-target completeness estimate. This is the load-bearing weak point: the central claim says 'we rule out all shorter-period aliases,' whereas the supplied evidence rules out only aliases with transits strong enough and clean enough to be found by this particular search.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper presents an automated alias-search analysis of 266 TESS planet candidates with reported orbital periods longer than 27 days, using multiple TESS data reductions. The authors report eight candidates whose periods should be shortened to an alias, six small ephemeris corrections, nine 'confirmed' and five 'likely' long-period (P > 100 d) candidates, and three candidates with possible transit timing variations. The central claim is that, despite the prevalence of alias degeneracies in TESS data, a meaningful set of cool long-period planet candidates survives scrutiny.","tokens_in":9,"tokens_out":6404,"duration_ms":86981,"significance":"If the nine confirmations hold up, the paper delivers one of the first sizable samples of TESS planets with periods beyond 100 days, including several with periods longer than the current record-holder TOI-4600 c. The analysis is careful in its use of multiple reductions, and the public code (Zenodo/GitHub) and the external validation by independent confirmations of TOI-4633 c and TOI-2088 b are clear strengths. The paper also provides useful period corrections and TTV targets. The main significance is as a reference catalog for follow-up of cool transiting planets, though the strength of the confirmation claims needs to be better quantified.","major_comments":[{"comment":"The confirmation of nine long-period candidates rests on the assertion that all shorter-period aliases are ruled out. The sensitivity analysis reports that at the adopted S = δD ≈ 0.135 threshold the detection rate is 70%, and even above that threshold it is about 90%, meaning roughly one in ten transits above the threshold is missed. The paper does not provide per-target signal strengths or a statistical calculation (e.g., a binomial probability) that the absence of detected transits at each shorter-period alias is significant. For candidates with only two or three expected transits at an alias, a 10% per-transit miss rate gives a non-negligible chance of missing all of them. Please add per-target S values and a per-alias exclusion probability, or soften the 'confirmed' language to 'likely' for targets where the expected number of alias transits is small.","section":"Section 2.4 and Table 3"},{"comment":"The 'Missing Aliases: None' entries in Table 3 are described as indicating that data exist at every alias, but the text in Section 3.3 also treats them as evidence that no alias transits were missed. Data coverage is not detection completeness; the sensitivity test in Figure 2 shows that even with data, transits are missed. The paper should distinguish 'no data gap at this alias' from 'a transit at this alias would have been detected,' for example by reporting the local noise level and expected signal strength at each alias epoch.","section":"Section 3.3 and Figure 2"},{"comment":"The sensitivity test is calibrated using the known transits of the same 266 TOIs, which is reasonable for estimating recall, but it does not characterize the false-positive rate of the search or the effect of correlated noise and data gaps at specific alias epochs. The authors should acknowledge this limitation explicitly and, ideally, perform a small injection-recovery test at the alias epochs of the nine confirmed candidates to demonstrate that a transit of the expected depth and duration would have been recovered.","section":"Section 2.4"}],"minor_comments":[{"comment":"The notation 'd »D 0.135' is garbled; please use 'δD ≈ 0.135' and define δ and D in the caption.","section":"Section 2.4, Figure 2 caption"},{"comment":"The new periods Pnew are quoted without uncertainties; please add the propagated uncertainty from the catalog period or state that the original uncertainty is unchanged.","section":"Table 1"},{"comment":"The phrase 'much larger than the initially reported error' is vague; consider quoting the ratio ΔP/σ_P for each target.","section":"Section 3.2"},{"comment":"The σ column is not defined in the table caption; please add a note that σ is the significance of the TTV relative to the combined uncertainty.","section":"Table 4"},{"comment":"The note for TOI-5975.01 says 'Long duration,' but it would be clearer to state explicitly whether this candidate has more than two transits and how the duration supports the long-period interpretation.","section":"Section 3.3"}],"recommendation":"major_revision","confidential_remarks":"The paper is already published (AJ 169:299, 2025). This report assesses the manuscript as submitted; the central completeness issue is fixable in principle, but as written the 'confirmed' language is stronger than the sensitivity analysis supports."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"This paper does exactly what the title says: it checks period aliases for 266 long-period TESS candidates and produces a concrete list—eight alias corrections, six ephemeris updates, nine confirmed long-period planets, five likely ones, and three possible TTVs. That is a citable, catalog-level contribution, and the code and diagnostic PDFs are public, so anyone can verify the calls. The authors deserve credit for being honest about the main limitation. They run a sensitivity test, report that the algorithm misses roughly a third of known transits overall and about 10% even above their S=0.135 threshold, and then explicitly mark the low-signal candidates as not confirmed. The seven 'very clear' confirmations in Section 3.3 all have multiple transits and high signal, which mitigates the completeness concern for those targets. The stress-test note makes a fair point: 'no transit found' does not mean 'no transit exists.' The phrase 'Missing Aliases: None' in Table 3 only says data were available at those epochs, not that a transit there would have been recovered. The paper could be more precise about this distinction, and per-target detection limits would strengthen the nine confirmations. But for the five 'Low signal!' cases, the authors already say they are too uncertain to confirm. So the central argument largely holds; the soft spot is in the labeling and phrasing, not in a hidden fatal flaw. The TTVs are flagged as 'possible' and rest on few transits. They are pointers for follow-up, not discoveries. The citation pattern is appropriate, including the independent confirmations of TOI-2088 b and TOI-4633 c. This paper is for the exoplanet follow-up community and anyone building samples of cool, long-period transiting planets. It will save people time by cleaning the TOI catalog and identifying the best targets for more costly observations. Yes, it deserves a serious referee. I would accept it with minor comments, mainly asking for clearer language about detection limits and, if feasible, per-target completeness estimates for the confirmed long-period candidates. The work is reproducible and the conclusions are proportionate to the evidence.","headline":"A careful, useful catalog paper that systematically checks TESS period aliases and confirms nine long-period candidates; the completeness caveat is real, but the authors hedge where it matters.","tokens_in":684,"tokens_out":1892,"would_cite":true,"duration_ms":32449,"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":"This paper establishes that nine TESS planet candidates have genuinely long orbital periods, while most longer-period TESS candidates are shorter-period aliases.","keywords":["transiting exoplanets","TESS","orbital period aliases","long-period planets","cool planets","transit timing variations","exoplanet catalogs","duo-transit candidates"],"falsifier":"Extend TESS or ground-based photometry on the five low-signal long-period candidates through their next predicted alias windows. A detected transit at half, one-third, or another integer fraction of the reported period, especially for TOI-699.03, TOI-1894.01, TOI-4348.01, TOI-4355.01, or TOI-4555.01, would disprove that candidate's long-period status. A transit below the $\\delta D \\approx 0.135$ threshold hidden in existing light curves could also be found by stacking or a deeper search, falsifying individual confirmations.","tokens_in":11,"feed_emoji":"🪐","tokens_out":6125,"duration_ms":104788,"temperature":0.7,"pith_summary":"This paper tries to settle which of TESS's long-period planet candidates really orbit their stars every 100-plus days and which are impostors reported at the wrong period. It runs an alias search over 266 TOIs with reported periods above 27 days, checking every possible integer fraction of each period against the light curves. The result is that most reported long periods, especially those over 500 days, are shorter-period aliases, but nine candidates are confirmed as genuinely long-period, with five more likely. Because long-period planets are cooler, the work enlarges the pool of cool transiting planets and points follow-up efforts at targets where a real signal exists.","feed_headline":"Nine TESS planet candidates keep long periods","feed_subtitle":"Alias search over TESS light curves confirms nine cool planets beyond 100 days and flags five more likely.","key_machinery":"The load-bearing object is the period-alias search built on the Farey sequence of the reported orbital period: for each TOI the code queries TESS light curves at times corresponding to rational fractions of the reported period up to 20th order, fits each potential transit, and checks that the depth and timing agree across independent data reductions. Its power is negative: a long period is confirmed only when no transit appears at any shorter-period alias. The sensitivity threshold $S = \\delta D \\approx 0.135$, the product of transit depth and duration, separates confident detections from low-signal cases; above it the search recovers about 90% of known transits, and below it roughly one third of real transits are missed.","core_discovery":"The paper's central claim is that the TESS catalog's long-period candidates split into two very different populations. For the overwhelming majority with reported periods longer than about 500 days, the two observed transits are separated by data gaps, and at integer fractions of the reported period one finds either no coverage or transits at the shorter period; these should be reclassified as shorter-period planets. In contrast, for fourteen TOIs the data cover all period aliases, and for nine of them the signal is strong enough to confirm true periods above 100 days, including seven marked as very clear with multiple transits, plus TOI-4633.01 and the clear duo-transit TOI-1894.01. The five remaining low-signal candidates are likely long-period but not certain. Alongside this central division, the paper corrects six periods by small amounts that would otherwise mimic transit timing variations, and reports three candidates with large, significant TTVs.","pith_inferences":["Editorial inference: The same alias-search approach can be re-run automatically on every future TESS release; the method's value grows with mission length, since each new sector fills in missing alias windows and can turn a likely candidate into a confirmed one.","Editorial inference: Because the five low-signal candidates have brighter hosts than typical Kepler long-period planets, follow-up photometry during predicted alias transits is a cheap and decisive test of the long-period hypothesis.","Editorial inference: The confirmed cool planets are natural targets for exomoon and ring searches, since large rings or moons are easier to sustain around cooler, more distant planets.","Editorial inference: The three TTV systems, with magnitudes near 11-12, could be used to measure planet masses dynamically; if the TTVs arise from companion planets, the bright hosts make them among the most accessible TTV systems known."],"forward_implications":["Most TOIs with reported periods over 500 days are duo-transits whose periods should be treated as upper limits, not true orbital periods; future catalogs should mark them as unconfirmed aliases.","The nine confirmed and five likely long-period planets give a target list of cool transiting planets, some brighter than Kepler's cool planets, suitable for radial-velocity and atmospheric follow-up.","Five candidates (TOI-699.03, TOI-1894.01, TOI-4348.01, TOI-4355.01, and TOI-4555.01) could become the longest-period TESS exoplanets once more data arrive, with several exceeding the current 482-day record.","Small uncorrected period errors build up to hour-level ephemeris offsets after tens of orbits, so the six corrected periods prevent false TTV detections.","The three newly reported TTV systems are bright stars where dynamical follow-up can look for companion planets."],"supporting_citations":[{"why":"Defines the TOI catalog, the source of all candidate periods and parameters analyzed here.","marker":"Guerrero et al. 2021"},{"why":"Describes the TESS mission and observing cycle whose repeated sectors create the period-alias problem.","marker":"Ricker et al. 2014"},{"why":"Supplies the Farey-sequence method for enumerating rational period aliases used by the search code.","marker":"Carter & Agol 2013"},{"why":"Documents the expected clump of roughly 700-day alias candidates from TESS's revisit schedule, motivating the analysis.","marker":"Cooke et al. 2021"},{"why":"Provides TOI-4600c, the 482-day confirmed planet that serves as the longest-period benchmark for TESS.","marker":"Mireles et al. 2023"},{"why":"Independent confirmation of TOI-4633 as a 271-day planet, corroborating the algorithm's alias detection.","marker":"Eisner et al. 2024"},{"why":"Supplies the Kepler KOI comparison sample of long-period planets used to place these candidates in context of brightness and temperature.","marker":"Thompson et al. 2018"}],"fun_headline_variants":["Nine TESS planets keep long periods; many don't","Alias check confirms nine cool TESS planets","TESS long-period planets: nine confirmed real","Cool TESS planets beyond 100 days: nine confirmed"],"cache_read_input_tokens":13056,"weakest_assumption_plain":"The confirmation that no shorter-period alias exists depends on the assumption that the algorithm's transit search, at its $\\delta D \\approx 0.135$ sensitivity threshold, would have seen any real alias transit; below that threshold about one-third of known transits are missed, so a shallow missed transit could make a long period appear confirmed when it is not.","fun_headline_variants_meta":{"raw":{"variants":["Nine TESS planets keep long periods; many don't","Alias check confirms nine cool TESS planets","TESS long-period planets: nine confirmed real","Cool TESS planets beyond 100 days: nine confirmed"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.001326,"raw_usage":{"total_tokens":5422,"prompt_tokens":999,"completion_tokens":4423,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":615,"completion_tokens_details":{"reasoning_tokens":4360}},"tokens_in":615,"tokens_out":4423,"duration_ms":30421,"temperature":1.0,"reasoning_tokens":4360,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-12T11:52:29.056089+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"Extend TESS or ground-based photometry on the five low-signal long-period candidates through their next predicted alias windows. A detected transit at half, one-third, or another integer fraction of the reported period, especially for TOI-699.03, TOI-1894.01, TOI-4348.01, TOI-4355.01, or TOI-4555.01, would disprove that candidate's long-period status. A transit below the $\\delta D \\approx 0.135$ threshold hidden in existing light curves could also be found by stacking or a deeper search, falsifying individual confirmations.","supporting_citations":[],"review_version":1}