The common light travel delay in TIC 300560295 permits at most 5.3 s of phase change for A ≤ 30 min, P₂ ≥ 1500 d, e₂ ≤ 0.6 and L ≤ 10.4 d

We test how a common light travel delay changes the position of a secondary eclipse between adjacent primary eclipses. Constant and linear delay cancel in this phase ratio. We prove a limit of 5.2842 s between epochs for TIC 300560295 when A = a_bin sin(i)/c is at most 30 min, the outer period is at least 1500 d, and outer eccentricity is at most 0.6. The inner primary interval is at most 10.4 d. We express phase as time with the reference period 10.294388 d. This assumed range contains the central outer orbit fits in the parent SCI paper. Separate fits to 42 native TESS light curves give 30 adjacent eclipse triples. Their early to late phase change is 29.6 min, with a local propagated error of 4.7 min. However, fixed-center residual noise trials have broad tails. Their central 95% range includes this fit change if all centers are kept. With the same fit rejection rules, 3 of 128 trials reach the measured change. These controls depend on the fitted noise model. A separate centroid check also fails to give stable early times. Thus a real half-hour phase change would require more than common light travel delay in this range, but these fits do not establish a precise change in conjunction time. We preserve unchanged native data subsets, source URLs and hashes, all event decisions, code, figures, noise draws, and reproduction instructions. This is a follow-up bound and uncertainty audit. The changing eclipses and reported triple are prior results.

TIC 300560295 · eclipsing binaries · TESS · light travel time · eclipse timing · uncertainty · reproducible astronomy