Run · HD 139139, the "Random Transiter"

TESS Sector 91: dip search, injection-recovery and false-alarm tests

The circular-shift null (seed 1, 3,000 realisations, candidate masked) gives a false-alarm probability below 1/3000. It reuses the same noise features and is overconfident; the independent check's 0.5–2 % is the figure to use. The figure's 'TARS (independent)' means an independent pipeline, not independent noise.

TESS S91 cannot test whether the dipping continues; its one candidate is marginal.{'candidate': {'btjd': 3778.5485, 'depth_ppm': 507, 'duration_h': 2.24, 'depth_err_ppm': 105}, 'expected_A': 0.44, 'expected_B': 0.7, 'completeness_A': 0.094, 'completeness_B': 0.149, 'fap_independent': '0.5-2%', 'real_detections': 1}0

Result

Run	Measured	Result	Against	Decision	Date
Run	Per-dip completeness and expected detections at the K2 rate (>=4.5 sigma); detections in real data	{'candidate': {'btjd': 3778.5485, 'depth_ppm': 507, 'duration_h': 2.24, 'depth_err_ppm': 105}, 'expected_A': 0.44, 'expected_B': 0.7, 'completeness_A': 0.094, 'completeness_B': 0.149, 'fap_independent': '0.5-2%', 'real_detections': 1}	Noise-only false alarms at >=4.5 sigma: 0.014 per 13.5 d (circular-shift null) · independent check with white and phase-randomised nulls gives FAP 0.6-1.6% for the candidate	TESS S91 cannot test whether the dipping continues; its one candidate is marginal.

What it used and found

Single-event dip search with injection-recovery and fair nulls

Method

MTH

TESS Sector 91 full-frame-image light curves at the position of HD 139139 (2025)

Dataset

DAT

Table of the 28 transit-like events (times, durations, depths)

Dataset

DAT

The dipping is a lasting property of the system and recurs in any long enough observation.

Answer it tests

ANS

One marginal dip-like event in TESS Sector 91 at BTJD 3778.55

Evidence it produced

EVD

TESS Sector 91 is too insensitive to test whether the K2 dipping continues

Evidence it produced

EVD

Parameters

n_trials = 1000, min_coverage = 0.9, rate_per_day = 0.338, depth_scale_B = 1.2, threshold_sigma = 4.5, clean_windows_btjd = [[3775.62, 3780.6], [3789.4, 3798.4]]

Cite it

Mysteries Department. (2026). TESS Sector 91: dip search, injection-recovery and false-alarm tests [Run RUN0DD2GVRRESBS]. https://mysteriesdept.com/r/RUN0DD2GVRRESBS

@misc{mysteriesdept_run0dd2gvrresbs,
  title     = {TESS Sector 91: dip search, injection-recovery and false-alarm tests},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Run, catalog key RUN0DD2GVRRESBS},
  url       = {https://mysteriesdept.com/r/RUN0DD2GVRRESBS}
}