Whenever Sol disobeys Pantheon, Pantheon destroys a star as a punishment. The destruction is treated as basically happening instantly, so this should be fairly simple.
Seeing as Runeterra is based off of Earth, it should serve a fair basis.
The distance from Earth to the nearest star (Proxima Centauri) is 4.2 Light Years
4.2 Lightyears = 3.974e+16 meters
3.974e+16 / 299792458 = 132,558,371 c
Not bad, not bad at all. Scales to all the other Aspects, and this is a pretty big lowball considering this is implied to have happened multiple times.