28 Cygni BRITE and SMEI satellite photometry

Observations with the Solar Mass Ejection Imager in 2003-2010 and 118 H{alpha} line profiles were added. For decades, 28 Cyg has exhibited four large-amplitude frequencies: two closely spaced frequencies of spectroscopically confirmed g modes near 1.5c/d, one slightly lower exophotospheric (Stefl) frequency, and at 0.05c/d the difference frequency between the two g modes.

This top-level framework is indistinguishable from eta Cen (Paper I), which is also very similar in spectral type, rotation rate, and viewing angle. The Stefl frequency is the only one that does not seem to be affected by the difference frequency. The amplitude of the latter undergoes large variations; around maximum the amount of near-circumstellar matter is increased, and the amplitude of the Stefl frequency grows by some factor.