The Stellar Combuster is a weapon of mass destruction developed by the refugee fleet that eventually became the Autonomous Diaspora. The weapon initiates a chain reaction within a star that generates a wave of destruction capable of consuming entire star clusters.
Eighty thousand years ago during the exodus, the proto-Diasporatic fleet detonated stellar combusters behind them as they fled across a bridge of stars connecting the Perseus and Sagittarius arms of the Milky Way galaxy to prevent Rigour from pursuing them.
More recently(about 20,000 years ago), the Diaspora again deployed stellar combusters when The Diaspora and Rigour met again at the second star bridge. This time the Diaspora attempted to draw Rigour itself into the star bridge and annihilate it in the ensuing firestorm.
As a sequelae to the stellar combusters detonation a web of light burns in the space where the stars were destroyed, a brilliant scar that only fades after tens of thousands of years.