Not a supernova, but a binary system hits 100 TeV, stuns particle physics

LHAASO detected gamma rays above 100 TeV from LS I +61° 303, a gamma-ray binary system.

This is the first confirmed detection of such ultra-high-energy gamma rays from a gamma-ray binary.

The signal changes with the binary’s orbit, pointing to a powerful and variable particle accelerator.

The source may be accelerating protons or heavier particles, not just electrons.

The result broadens the list of possible sources of the Milky Way’s highest-energy cosmic rays.