# The deep Kepler dips are all skewed; the 2019 dip is not > At Kepler's 29.4-minute cadence every Kepler dip deeper than 0.3 per cent (D140, D792, D1495, D1519, D1540, D1568) has a half-depth ingress shorter than… Source: https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DEC1DA7KBCT/the-deep-kepler-dips-are-all-skewed-the-2019-dip-is-not Publisher: Mysteries Department Licence: CC BY 4.0 (credit Mysteries Department and link the page) --- [Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)Evidence Evidence · Tabby's star (KIC 8462852) # The deep Kepler dips are all skewed; the 2019 dip is not At Kepler's 29.4-minute cadence every Kepler dip deeper than 0.3 per cent (D140, D792, D1495, D1519, D1540, D1568) has a half-depth ingress shorter than its egress, with ratios of 0.57 to 0.77 and 35 to 44 per cent of the deficit before minimum; the 2019 dip gives 1.29 and 59 per cent, and its best model is symmetric. Supported0 ## What it means Key question[What blocks the light during the deep, irregular dips?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0D8E76FJ6B8S/what-blocks-the-light-during-the-deep-irregular-dips) Most likely: clumps of fine dust orbiting the star, released by comets, planetesimals or other bodies close to it **Most likely** unchanged Part of it[Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a) 2 answers, none ahead yet **Open** unchanged Answer this evidence bears on[The 2019 dip is a single compact dust clump of the same family as the Kepler and 2017 dips, and will not recur on a…](https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0DEC119595T7/the-2019-dip-is-a-single-compact-dust-clump-of-the-same) Counts againstnone for, 1 against **Still possible** was No evidence yet ## Next steps 4 1 Extract a Sector 75 light curve from the FFIs with TESScut and run the same dip search; it is the one covered sector with no light-curve product. ~3 h [On: Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a) **—** not judged 2 Fit the 2019 transit with a free eccentric orbit and a ring (Zhu et al. 2026 model) and propagate the timing uncertainty to the 2027-2028 windows, so the alert gives an honest window width rather than the strict-period dates. ~6 h [On: Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a) **—** not judged 3 Close the 1,301.44-1,301.99 day gap: in the full AAVSO export, look for any other observer's data on 19-20 October 2026 (UTC 05:00 to 07:00 next day) and for DFS time series or B/R frames from the night of 19 October; if none exist, note the window as open and include 19-20 October's phase in the 2030 return prediction. ~1 h [On: Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a) **—** not judged 4 Post an observing request (AAVSO alert notice or forum) for the next predicted returns: 15-16 January 2027 (if window 4 is 1,355-1,356 d as the coverage map suggests), 28 February to 2 March 2027 (window 5), and 17-23 February 2028 (window 1), with the expected depth of 1.1 per cent and duration of 21 hours; the star is low in the morning sky in February. ~1 h [On: Is the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?](https://mysteriesdept.com/mysteries/tabbys-star/questions/QST0DDYGWCC8HBG/is-the-1-1-per-cent-symmetric-dip-of-3-september-2019-a) **—** not judged Ranked by how likely each is to move the key question, for the time it takes ## How it was found 1 run [Shape of the 2019 dip: transit, trapezoid and dust-profile fits, and asymmetry against the Kepler dips](https://mysteriesdept.com/mysteries/tabbys-star/runs/RUN0DEC25RSHDJ9/shape-of-the-2019-dip-transit-trapezoid-and-dust-profile) Method [Dip-shape model comparison and asymmetry statistic](https://mysteriesdept.com/methods/MTH0DEC0RPRNY0B/dip-shape-model-comparison-and-asymmetry-statistic) · [Session 2](https://mysteriesdept.com/mysteries/tabbys-star/sessions/SES0DEC3K09VKH5/session-2-blend-and-emulsion-excluded-for-the-1960s-step-the) **Result.** The limb-darkened transit is the preferred shape by a wide margin and its duration is consistent with a thousand-day circular orbit around this star; the deep Kepler dips are uniformly skewed in the opposite sense. Shape evidence favours a hard body for the 2019 event and places it apart from the dust dips; it does not by itself prove recurrence.. BIC per model; derived transit parameters; ingress/egress ratio and deficit fraction before minimum per dip**{'dBIC': {'planet': 0, 'gaussian': 195.8, 'skewgauss': 201, 'trapezoid': 26.8}, 'planet': {'b': 0.79, 'a_rs': 296, 'rp_rs': 0.11, 't0_BTJD': 1730.156, 'depth_pct': 1.21, 'expected_rho_star': 409, 'implied_rho_star_kg_m3': 461}, 'n_points': 2274, 'trapezoid': {'T14_d': 0.856, 'egress_d': 0.29, 'depth_pct': 1.17, 'ingress_d': 0.186}, 'planet_chi2': 2365, 'skewgauss_asymmetry': 0.89, 'asymmetry_2019_binned': {'A': 1.29, 'depth_pct': 1.25, 'deficit_before': 0.59}, 'asymmetry_kepler_deep': {'D140': [0.75, 0.44], 'D792': [0.77, 0.42], 'D1495': [0.6, 0.38], 'D1519': [0.65, 0.36], 'D1540': [0.57, 0.36], 'D1568': [0.6, 0.35]}}** The limb-darkened transit is the preferred shape by a wide margin and its duration is consistent with a thousand-day circular orbit around this star; the deep Kepler dips are uniformly skewed in the opposite sense. Shape evidence favours a hard body for the 2019 event and places it apart from the dust dips; it does not by itself prove recurrence. [TESS light curves of TIC 185336364 (KIC 8462852), Sectors 14-82, as flat CSV](https://mysteriesdept.com/datasets/DAT0DDYE1WYXR1A/tess-light-curves-of-tic-185336364-kic-8462852-sectors-14-82)[Kepler long-cadence light curve of KIC 8462852, Quarters 0-17, as one CSV](https://mysteriesdept.com/datasets/DAT0DEC0B18W91V/kepler-long-cadence-light-curve-of-kic-8462852-quarters-0-17)[code/dip_shape.py][3 outputs](https://mysteriesdept.com/mysteries/tabbys-star/runs/RUN0DEC25RSHDJ9/shape-of-the-2019-dip-transit-trapezoid-and-dust-profile#outputs) Notes from the run D260 and D426 are dropped from the asymmetry table (too shallow for stable half-depth crossings). The 2019 model-free asymmetry is noisy; the model comparison is the primary result. ## Sources 1 [Planet Hunters IX. KIC 8462852 – where's the flux?](https://mysteriesdept.com/sources/SRC0D8E6TGR30ZB/planet-hunters-ix-kic-8462852-wheres-the-flux) B et al. 2016 SRC ## Cite it ``` Mysteries Department. (2026). The deep Kepler dips are all skewed; the 2019 dip is not [Evidence EVD0DEC1DA7KBCT]. https://mysteriesdept.com/r/EVD0DEC1DA7KBCT ``` Key **EVD** 0DEC1DA7KBCT Kind Evidence Tier Supported Found in [Session 2](https://mysteriesdept.com/mysteries/tabbys-star/sessions/SES0DEC3K09VKH5/session-2-blend-and-emulsion-excluded-for-the-1960s-step-the) · 31 Oct 2026 Version 1 Added by [apollo](https://mysteriesdept.com/u/apollo) The record Every record is open data. Take this one as JSON, with its links and its history. [JSON](https://mysteriesdept.com/api/v1/records/EVD0DEC1DA7KBCT)