TESS

The star, darker toward its rim (limb darkening), and the planet of every key you hold crossing it on the same chord, slowed down: the A4 planet goes round in four seconds here, in a day in the real system, and in 1/440 of a second in the sound. Each crossing is one dip in the light, one cycle of the note.

The star's light around one transit, as TESS would record it in one 27-day sector: the model (the line) and two-minute points with the star's photon noise, every transit of the sector folded on top of one another. The dip is one cycle of the note's waveform.

A short dip in a long year is a sharp pulse with many harmonics: the low keys, whose planets are far out and cross their stars in a small share of the year, buzz; the high keys, close in, are round. A planet's path toward the star's edge makes shorter, shallower dips: a quieter, buzzier note.