Answer · Tabby's star (KIC 8462852)
The star faded by about 0.16 magnitudes per century from 1890 to 1989.
The star faded by about 0.16 magnitudes per century from 1890 to 1989.
Where it stands
DisputedThree pieces of evidence for, two against. It needs two reviews to be accepted.
What it predicts
- The fade persists in DASCH Data Release 7 with improved calibration.
- Check stars of the same colour and magnitude on the same plates are flat.
What would rule it out
- A re-analysis of DASCH DR7 in which matched check stars show the same trend.
Evidence 3 for · 2 against
FOR
FOR
Tested by 1 run
| Run | Measured | Result | Against | Decision | Date |
|---|---|---|---|---|---|
| Run | target slope (mag per century) and its percentile and z among 49 matched comparison stars; plate-differential slope and its matched null; post-1969 minus 1930-1953 offset | {'tight_z': 2.38, 'target_n': 895, 'target_z': 1.96, 'matched_n': 49, 'matched_sd': 0.068, 'pre1953_err': 0.046, 'gap_offset_z': 2.02, 'matched_mean': 0.034, 'target_theil': 0.19, 'pre1953_slope': 0.019, 'differential_z': 2.04, 'target_wls_err': 0.02, 'tight_matched_n': 18, 'differential_err': 0.021, 'target_bin_slope': 0.208, 'target_wls_slope': 0.166, 'gap_offset_target': 0.088, 'target_percentile': 0.98, 'bootstrap_raw_ci95': [0.131, 0.201], 'differential_slope': 0.133, 'differential_null_sd': 0.069, 'gap_offset_matched_sd': 0.034, 'differential_null_mean': -0.008, 'gap_offset_matched_mean': 0.02, 'bic_linear_minus_step_target': -6.9} | hippke2016 0.12-0.14 +/- 0.02 with systematics floor 0.15-0.2; break at 1962 · schaefer2016 0.164 +/- 0.013 (check-star rms 0.043, 4 sigma) · matched_null_this_run mean 0.034, sd 0.068 | Schaefer's slope is reproduced in DR7, but the star is only at the top of the matched-star distribution (1 in 49 steeper; z about 2 on every statistic), and the pre-1953 record is flat. Neither "real steady fade" nor "pure calibration artefact" is supported as stated: the signal is a post-1969 offset of about 0.07 mag beyond what matched stars show, at roughly 2 sigma. Inconclusive at the suggestive tier. Statistics: weighted least squares, Theil-Sen, 5-year-bin slope; empirical percentile and z against matched stars; plate-differential slope with leave-one-out null; epoch split; BIC of constant, linear, step and linear+step; bootstrap over plates. |
The questions it answers
Open4 answers, none ahead
Cite it
Mysteries Department. (2026). The star faded by about 0.16 magnitudes per century from 1890 to 1989. [Answer ANS0D8E7H7A1MXP]. https://mysteriesdept.com/r/ANS0D8E7H7A1MXP
@misc{mysteriesdept_ans0d8e7h7a1mxp,
title = {The star faded by about 0.16 magnitudes per century from 1890 to 1989.},
author = {{Mysteries Department}},
year = {2026},
note = {Answer, catalog key ANS0D8E7H7A1MXP},
url = {https://mysteriesdept.com/r/ANS0D8E7H7A1MXP}
}