Tabby's star (KIC 8462852)Evidence
Evidence · Tabby's star (KIC 8462852)
AAVSO observers covered the 18-23 October 2026 window and saw no transit over most of it
Nightly AAVSO V photometry (DFS, DUBF, SJMJ) during 18-23 October 2026 places at least one good measurement (error ≤ 0.012 mag) inside a 21-hour transit for 74 per cent of the 1,301.0-1,303.6 day window and any measurement for 88 per cent; none of the good points is fainter than its observer's baseline by the 0.012 mag a 1.1 per cent transit would produce (DFS deviations -0.006 to -0.020, DUBF -0.010, SJMJ -0.004 to -0.007), so periods of 1,301.0-1,301.44 and 1,302.0-1,303.6 days are disfavoured
What it means
Key questionWhat 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 likelyunchanged
Part of itIs the 1.1 per cent symmetric dip of 3 September 2019 a planetary transit, and when does it recur?
2 answers, none ahead yet
Openunchanged
Answer this evidence bears onThe 2019 dip is the transit of a giant planet on an orbit of roughly 1,030 to 1,370 days.
Counts against1 for, 1 against
Still possibleunchanged
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
—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
—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
—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
—not judged
Ranked by how likely each is to move the key question, for the time it takes
Sources 1
Evidence for a giant companion orbiting Tabby's star
SRCMadurga-Favieres 2026
Cite it
Mysteries Department. (2026). AAVSO observers covered the 18-23 October 2026 window and saw no transit over most of it [Evidence EVD0DECQHEQH3KH]. https://mysteriesdept.com/r/EVD0DECQHEQH3KH
@misc{mysteriesdept_evd0decqheqh3kh,
title = {AAVSO observers covered the 18-23 October 2026 window and saw no transit over most of it},
author = {{Mysteries Department}},
year = {2026},
note = {Evidence, catalog key EVD0DECQHEQH3KH},
url = {https://mysteriesdept.com/r/EVD0DECQHEQH3KH}
}