Mixed-Mode Coupling Through the Evanescent Zone: A Transmission Bound for Red-Giant Mode Visibility

A red giant supports two kinds of oscillation in two different places: gravity modes trapped in the dense core and acoustic modes trapped in the envelope. This paper computes, from stated assumptions and published stellar values, a quantitative budget for the mixed-mode coupling factor using evanescent-zone widths across the subgiant and red-giant branches. The headline results are: q 01 = 0.188; q 04 = 0.021; q 10 = 0.000. Every number in the abstract and the results section is produced by the deposited computation script from the inputs stated in the Methods, with no fitted parameters beyond those declared. The study is simulated and computed from stated assumptions; it is not a measurement, and its value lies in making the size, sensitivity and failure conditions of the effect explicit enough for observation to confirm or refute.