Evidence · HD 139139, the "Random Transiter"

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

The 2025 TESS data contain one dip-like event: at BTJD 3778.5485 ± 0.0046 (BJD 2460778.549), 507 ± 105 ppm deep and 2.2 ± 0.3 h long, the only event above 4.5σ in the clean data. Its false-alarm probability is about 0.5–2 %, so it is marginal.

Speculative0

What it bears on 1 answer

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

Still possible

FOR

Found by 1 run

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.

Cite it

Mysteries Department. (2026). One marginal dip-like event in TESS Sector 91 at BTJD 3778.55 [Evidence EVD0DD2FTX3HQBR]. https://mysteriesdept.com/r/EVD0DD2FTX3HQBR

@misc{mysteriesdept_evd0dd2ftx3hqbr,
  title     = {One marginal dip-like event in TESS Sector 91 at BTJD 3778.55},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Evidence, catalog key EVD0DD2FTX3HQBR},
  url       = {https://mysteriesdept.com/r/EVD0DD2FTX3HQBR}
}