Later astrometry confirms published near-Earth asteroid Yarkovsky drifts only as much as a size-based physical prior predicts (228 asteroids, MPC data 2012-2026)

Question: do published Yarkovsky drift rates of near-Earth asteroids (NEAs) predict their positions in astrometry made after the catalogue data cut-off? Approach: for the catalogues of Greenberg et al. (2020; MPC data to 2019-11-11) and Nugent et al. (2012; data to 2012-01-31), we fitted each orbit with an independent N-body code (ASSIST/REBOUND, DE440) to the MPC optical data before the cut-off, once with gravity only and once with the published drift as a fixed transverse acceleration. We measured the fraction k of the predicted extra sky shift that the later MPC data show (k = 1: drift correct; k = 0: no drift). Results: our fits of the training data reproduce the published values (r = 0.94-0.96). For 184 testable Greenberg asteroids, the random-effects mean is k = 0.76 +/- 0.03; for 44 testable Nugent asteroids, k = 0.41 +/- 0.09. The published signal-to-noise ratio does not rank reliability below SNR 5 (Spearman p = 0.24); drifts with SNR >= 5 give k = 0.95 +/- 0.03. A zero-mean prior on the Yarkovsky efficiency (scale 0.079 from SNR >= 5 values, catalogue diameters, density 2000 kg/m3) predicts k without a fit to the test data: k = 0.01 + 1.07 k_prior (Greenberg) and -0.02 + 1.00 k_prior (Nugent). Asteroids for which the prior expects k < 0.5 have median k = 0.19 (75 asteroids); the others have median k = 0.91 (153). Greenberg drifts that need efficiency > 0.5 (flag S) give k = 0.12 +/- 0.07, except comet-asteroid 4015 Wilson-Harrington. Results do not change when observations with unknown star catalogues are removed (per-object r = 0.994). Limitations: simpler weights than the original authors, formal k errors too small (between-object scatter about 0.3-0.6), generic density and H-based diameters in the prior, and a Nugent prior scale that uses Greenberg values with 2012-2019 data.

Yarkovsky effect · near-Earth asteroids · orbit determination · astrometry · forecast test · winner's curse · non-gravitational acceleration · ASSIST · Minor Planet Center