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

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

Source: https://mysteriesdept.com/mysteries/tabbys-star/answers/ANS0DEC112MA2C4/the-2019-dip-is-the-transit-of-a-giant-planet-on-an-orbit-of  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

---

[Questions](https://mysteriesdept.com/questions)[Tabby's star (KIC 8462852)](https://mysteriesdept.com/mysteries/tabbys-star)[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)Answer

Answer · Tabby's star (KIC 8462852)

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

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

**Still possible** Answers **1** question0

## Where it stands

**Still possible** One piece of evidence for, one against. It needs two reviews to be accepted.

## What it predicts

- A transit of about 1.1 per cent and 21 hours at a date in one of the allowed windows (next: late February 2027 for the 1,345-1,368 day windows; mid-February 2028 for the 1,030 day window).
- No transit of that depth at any other time.
- The transit shape is symmetric and limb-darkened, unlike the structured Kepler dips.
- The radial-velocity signal grows past 3 sigma with more SOPHIE epochs.

## What would rule it out

- Continuous photometry through every allowed window with no transit.
- Radial velocities that exclude a companion above about 1 Jupiter mass at those periods.

## Evidence 1 for · 1 against

[The 2019 dip has the shape of a limb-darkened transit, not a dust cloud](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DEC1D3F7E1G/the-2019-dip-has-the-shape-of-a-limb-darkened-transit-not-a)

Supported

FOR

[AAVSO observers covered the 18-23 October 2026 window and saw no transit over most of it](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DECQHEQH3KH/aavso-observers-covered-the-18-23-october-2026-window-and)

Suggestive

AGAINST

[Kepler and TESS coverage alone exclude 80 per cent of periods and reproduce the published windows](https://mysteriesdept.com/mysteries/tabbys-star/evidence/EVD0DEC1DH5506X/kepler-and-tess-coverage-alone-exclude-80-per-cent-of)

Established

NEUTRAL

## Tested by 1 run

| 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. | |

## The questions it answers

[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)

Part of [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)

Open2 answers, none ahead

## Cite it

```
Mysteries Department. (2026). The 2019 dip is the transit of a giant planet on an orbit of roughly 1,030 to 1,370 days. [Answer ANS0DEC112MA2C4]. https://mysteriesdept.com/r/ANS0DEC112MA2C4
```

Key

**ANS** 0DEC112MA2C4

Kind

Answer · hypothesis

Proposed

[Session 2](https://mysteriesdept.com/mysteries/tabbys-star/sessions/SES0DEC3K09VKH5/session-2-blend-and-emulsion-excluded-for-the-1960s-step-the) · 31 Oct 2026

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