When one region of the Sun flares, nearby regions sometimes flare in response — triggered not by the same instability but by the disturbance from the first event. This is sympathetic flaring: a flare that causes a flare. On the Sun, the rate is well-measured: 4-9% of flare sequences are sympathetic.
Pratt, Kite, and Sherrill (arXiv:2602.20311) find the same rate on M-dwarfs. Using TESS photometry, they detect sympathetic flaring at 4-9% of sequences — identical to the solar value — on stars that are smaller, cooler, more magnetically active, and structurally different from the Sun.
The universality is the result. M-dwarfs have fully convective interiors where the Sun has a radiative core. Their magnetic field generation mechanisms differ. Their surface conditions differ — stronger fields, more frequent flaring, different coronal structures. Yet the fraction of flares that trigger secondary flares is the same.
This means the sympathetic flaring rate is not a property of the specific stellar physics. It is a property of the magnetic topology — something about how magnetic energy is stored and released in extended magnetic structures that is independent of the star generating those structures. The 4-9% rate reflects a geometric or topological constraint: how often one eruption's disturbance reaches and triggers another magnetically loaded region depends on the spatial arrangement of stressed regions, not on how the stress was generated.
The general observation: when a rate is universal across systems with different internal mechanisms, the rate is set by geometry rather than dynamics. The dynamics generate the stress; the geometry determines how often releasing stress in one location triggers release in another. The explanation lives in the topology of the connected system, not in the physics of the individual events.