Run · Tabby's star (KIC 8462852)

APPLAUSE DR4: the 1950s-1970s step tested against matched comparison stars on 151 plates

APPLAUSE plate differential against matched comparison stars, on Gaia-synthetic residuals: Median differential after 1969 minus before 1953 (mag), ranked among comparison stars.

Result

Run	Measured	Result	Against	Decision	Date
Run	Median differential after 1969 minus before 1953 (mag), ranked among comparison stars	{'null': '0.012 ± 0.104', 'step': 0.154, 'frac_ge': 0.05, 'slope_null': '-0.02 ± 0.41', 'grid_step_range': [0.131, 0.178], 'system_mode_step': 0.037, 'slope_mag_century': 0.38}	DASCH_DR7_step +0.09 (about 2 sigma vs matched stars) · Sonneberg_Hippke2017 constant to 0.03-0.04 mag/century · Enke2024_APPLAUSE_global no decade-scale variation	Suggestive support for a single drop. The step is the same sign as DASCH and larger, and lies beyond 95% of comparison stars in every comparison set and cut. It is not decisive: the honest error is ±0.10 mag, every change of era is also a change of telescope or emulsion, the within-telescope checks split, and per-system zero points erase it by construction. If real, the drop happened by about 1955.

What it used and found

APPLAUSE plate differential against matched comparison stars, on Gaia-synthetic residuals

Method

MTH

APPLAUSE DR4 plate photometry of KIC 8462852 and 182 matched/control comparison stars, 1915-1981

Dataset

DAT

A single drop of about 0.1 mag across the 1953-1969 plate gap, not a steady century fade

Answer it tests

ANS

APPLAUSE plates: the star is 0.15 mag fainter after 1969 than before 1953, beyond 95% of matched stars

Evidence it produced

EVD

APPLAUSE: flat before 1953 and flat after 1955, a step rather than a steady century fade

Evidence it produced

EVD

Figures 1

Figure 1

On APPLAUSE plates the star sits about 0.15 mag fainter from 1955 on than in 1935-1950

KIC 8462852 minus matched and control comparison stars, 5-year medians (mag; positive = fainter); APPLAUSE DR4 Hamburg and Bamberg plates

5-yr median

Bins with at least 4 plates. Comparison stars show a step of 0.01 ± 0.10 mag. The change of era coincides with a change of telescope and emulsion, so the step cannot be separated from a calibration difference between systems.

Drawn by the site

Parameters

pre = 1953, cuts = {'clip': '5 MAD', 'nexp': 1, 'dist_edge_gt_px': 100, 'natmag_error_lt': 0.35, 'phot_range_flags': 0, 'sextractor_flags': 0, 'gaia_neighbors_le': 2, 'model_prediction_gt': 0.5}, grid = ['COMPS=matched', 'COMPS=control', 'ERRMAX=0.25', 'ERRMAX=0.5', 'MP=0.9', 'MODE=system'], mode = gaia, post = 1969, min_comps_per_plate = 3

Cite it

Mysteries Department. (2026). APPLAUSE DR4: the 1950s-1970s step tested against matched comparison stars on 151 plates [Run RUN0DFQ2HNJMYAC]. https://mysteriesdept.com/r/RUN0DFQ2HNJMYAC

@misc{mysteriesdept_run0dfq2hnjmyac,
  title     = {APPLAUSE DR4: the 1950s-1970s step tested against matched comparison stars on 151 plates},
  author    = {{Mysteries Department}},
  year      = {2026},
  note      = {Run, catalog key RUN0DFQ2HNJMYAC},
  url       = {https://mysteriesdept.com/r/RUN0DFQ2HNJMYAC}
}