Same Depth Needs the Same Radius-Ratio Source - Observational Astrophysics: Distance, Flux, Transits, and Spectra Step by Step

Two systems show the same transit depth only when their planet-to-star radius ratio is the same, since depth = (Rp / Rstar)^2. Equal dips do not require equal planet radii, only equal ratios. This is the ideal uniform-disk result; real comparisons must correct for limb-darkening, inclination, and contamination before matching depths.

A repeated depth display must share the actual checked source. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A repeated depth display shares the same checked source

Both statements cite the same depth 1/25 from one radius-ratio source.

\text{source depth}=\tfrac{1}{25}

The radius ratio is the source of the depth

The accepted source has radius ratio 1/5; a copied depth from another source is rejected.

\left(\tfrac{1}{5}\right)^{2}=\tfrac{1}{25}