Mass loss during black hole formation in V404 Cygni

Ascertain whether any mass was ejected during the formation of the approximately 9 solar mass black hole in V404 Cygni and quantify the amount of mass loss, given constraints from the retention of the wide tertiary companion that favor small natal kicks and render sudden ejection of more than half the progenitor’s mass improbable.

Background

The authors simulate triple-system dynamics to assess which combinations of natal kick, mass loss, and initial orbital configurations could retain the loosely bound tertiary. Scenarios where the inner binary started in a tight orbit strongly constrain any sudden mass ejection because Blaauw kicks from mass loss would eject the tertiary; wider initial orbits with Kozai-Lidov migration also favor small kicks.

While the results indicate that near-complete implosion without substantial mass loss is consistent with the observed system, an exact determination of whether mass was ejected and how much remains unresolved. Establishing mass loss would directly test black hole formation pathways (e.g., direct collapse vs. supernova with ejection).