QuestionsHD 139139, the "Random Transiter"Are the 28 dips real changes in starlight, or an instrumental effect?Answer
Answer · HD 139139, the "Random Transiter"
The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.
Where it stands
Still possibleIts tests haven't settled it: one piece of evidence for, two against. It needs two reviews to be accepted.
What it predicts
- Similar random, shallow dips in other K2 C15 targets on the same detector module.
- The dips weaken or vanish in some reductions.
What would rule it out
- The dips found again in independent data from another telescope.
Evidence 1 for · 2 against
AGAINST
AGAINST
Tested by 2 runs
| Run | Measured | Result | Against | Decision | Date |
|---|---|---|---|---|---|
| Run | chi2 of stacked 27-dip deficit vs 'real dimming' and 'bleed column only' (null covariance); depth chi2 vs one amplitude; timing KS/permutation p-values | {'pointing_p': [0.93, 0.96], 'arclength_p': 0.73, 'column_only': {'dof': 2, 'chi2': 0.55}, 'real_dimming': {'dof': 2, 'chi2': 1.03, 'depth_ppm': 211}, 'spot_level_p': 0.3, 'no_signal_chi2': 324, 'thruster_phase_p': 0.52, 'depth_chi2_rednoise': '124/26', 'depth_chi2_published_errors': '184/26'} | 600 random non-dip epochs with the same procedure | Not a fixed-amplitude telegraph pixel and not tied to spacecraft motion; the pixels can't separate real dimming from a glitch confined to the saturated bleed column. | |
| Run | excess = dips - sign-flipped bumps at >=5.5 sigma, events >=1.5 h, K2SFF | {'rank': 5, 'n_stars': 619, 'HD139139': 15, 'population_quantiles_50_90_99': [0, 1, 9.6]} | The same statistic across 619 stars of Tmag 8.6-9.7 in C15 | HD 139139 is the only quiet star with an excess of random, multi-hour dips; the four ranked above it are periodic or active stars. Not a generic saturated-star artefact. |
The questions it answers
Most likelyThe dips are astrophysical, on star A or star B
Cite it
Mysteries Department. (2026). The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data. [Answer ANS0D79S1JY7DXT]. https://mysteriesdept.com/r/ANS0D79S1JY7DXT
@misc{mysteriesdept_ans0d79s1jy7dxt,
title = {The dips are an undiagnosed instrumental or data-processing effect in the K2 Campaign 15 data.},
author = {{Mysteries Department}},
year = {2026},
note = {Answer, catalog key ANS0D79S1JY7DXT},
url = {https://mysteriesdept.com/r/ANS0D79S1JY7DXT}
}