Origin of Galactic-centre hypervelocity stars

Determine the origin of hypervelocity stars ejected from the Galactic centre in a manner consistent with the gas-shell fragmentation scenario for forming the S cluster.

Background

The paper evaluates gas-shell fragmentation driven by a brief Sgr A* outflow as an in situ formation channel for the young S-cluster stars. Although this scenario accounts for several observed properties of the cluster, the authors identify the origin of hypervelocity stars from the Galactic centre as a principal unresolved difficulty. They note that rare ejections from bound binaries might provide a possible contribution, but do not establish that this mechanism explains the observed hypervelocity-star population.

References

Its main difficulties are the unclear origin of hypervelocity stars from the Galactic centre \citep[e.g.][]{2020MNRAS.491.2465K,2026A&A...709A.117C}, although rare ejections from bound binaries might help \citep{2026A&A...706A..63S}, and the need for a super-Eddington event plus a cloud with low angular momentum \citep{2018MNRAS.478L.127N}.

— A solution to the paradox of youth in the Galactic centre  (2609.31305 - Silva et al., 25 Sep 2026) in Section 1, Introduction