Run · Tabby's star (KIC 8462852)

Period exclusion and transit windows for the 2019 dip from Kepler and TESS coverage

Kepler and TESS coverage intervals are read from the data files; 2015-2018 ground photometry is not used for exclusion. Future TESS sectors (expected 2027) are not in the coverage table.

Coverage alone reproduces the published windows 1, 3 and 5 and shows windows 2 and 4 as printed are excluded (typographical). The most recent predicted return, window 3 on 18-23 October 2026, had no space coverage; the next falls in January to March 2027 near solar conjunction, then 17-23 February 2028. The recurrence model is essentially untested by TESS.{'next_transits': {'W1': ['2022-06-29..07-01 (8 d before S54)', '2025-04-24..27', '2028-02-17..23'], 'W3': ['2023-03-27..30', '2026-10-18..23', '2030-05-11..19'], 'W4': ['2023-05-11', '2027-01-15..16'], 'W5': ['2023-06-01..02', '2027-02-28..03-02']}, 'W1_survives_because': '2011-03-15..20 falls in the Q8/Q9 gap', 'coverage_days_total': 1522.6, 'excluded_as_printed': {'W2': 'Kepler 2011-03-03..06', 'W4': 'Kepler 2012-04-21'}, 'allowed_near_published': {'W1': [1029.45, 1031.7], 'W3': [1300.2, 1304.05], 'W5': [1365.85, 1368.5], 'nearest_to_W4': [1354.4, 1356.1]}, 'fraction_excluded_100_3000d': 0.804, 'recurrence_coverage_fraction': {'n1_2013': 0.56, 'n4_2019': 0.07, 'n5_2021': 0.09, 'n6_2024': 0.05}}0

Result

Run	Measured	Result	Against	Decision	Date
Run	Fraction of periods excluded; allowed ranges; per-window past/next transit dates and coverage; recurrence-window coverage fractions	{'next_transits': {'W1': ['2022-06-29..07-01 (8 d before S54)', '2025-04-24..27', '2028-02-17..23'], 'W3': ['2023-03-27..30', '2026-10-18..23', '2030-05-11..19'], 'W4': ['2023-05-11', '2027-01-15..16'], 'W5': ['2023-06-01..02', '2027-02-28..03-02']}, 'W1_survives_because': '2011-03-15..20 falls in the Q8/Q9 gap', 'coverage_days_total': 1522.6, 'excluded_as_printed': {'W2': 'Kepler 2011-03-03..06', 'W4': 'Kepler 2012-04-21'}, 'allowed_near_published': {'W1': [1029.45, 1031.7], 'W3': [1300.2, 1304.05], 'W5': [1365.85, 1368.5], 'nearest_to_W4': [1354.4, 1356.1]}, 'fraction_excluded_100_3000d': 0.804, 'recurrence_coverage_fraction': {'n1_2013': 0.56, 'n4_2019': 0.07, 'n5_2021': 0.09, 'n6_2024': 0.05}}		Coverage alone reproduces the published windows 1, 3 and 5 and shows windows 2 and 4 as printed are excluded (typographical). The most recent predicted return, window 3 on 18-23 October 2026, had no space coverage; the next falls in January to March 2027 near solar conjunction, then 17-23 February 2028. The recurrence model is essentially untested by TESS.

What it used and found

Coverage-based period exclusion and transit-window table for a single observed transit

Method

MTH

Kepler long-cadence light curve of KIC 8462852, Quarters 0-17, as one CSV

Dataset

DAT

TESS light curves of TIC 185336364 (KIC 8462852), Sectors 14-82, as flat CSV

Dataset

DAT

The 2019 dip is the transit of a giant planet on an orbit of roughly 1,030 to 1,370 days.

Answer it tests

ANS

Kepler and TESS coverage alone exclude 80 per cent of periods and reproduce the published windows

Evidence it produced

EVD

TESS covered under a tenth of the recurrence model's predicted windows

Evidence it produced

EVD

Parameters

T0_BJD = 2458730.164, duration_d = 0.85, recurrence = {'P': [781.63, 776.106], 'sigma_P': 79.99, 't0_BKJD': 792.7}, gap_split_d = 1, period_grid_d = [100, 3000, 0.05], published_windows_d = {'W1': [1029.7, 1031.5], 'W2': [1034.5, 1035.3], 'W3': [1301, 1303.6], 'W4': [1345.6, 1345.7], 'W5': [1367.3, 1368.3]}

Cite it

Mysteries Department. (2026). Period exclusion and transit windows for the 2019 dip from Kepler and TESS coverage [Run RUN0DEC25J1X101]. https://mysteriesdept.com/r/RUN0DEC25J1X101

@misc{mysteriesdept_run0dec25j1x101,
  title     = {Period exclusion and transit windows for the 2019 dip from Kepler and TESS coverage},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Run, catalog key RUN0DEC25J1X101},
  url       = {https://mysteriesdept.com/r/RUN0DEC25J1X101}
}