Formation channel of the required eccentric compact orbit

Identify the formation channel capable of producing the highly eccentric and tight orbit required for an orbiter-disk-collision model to launch the observed mildly relativistic outflows.

Background

Under the hypothesis that the eruptions arise from collisions between an orbiting object and the accretion disk, the measured outflow velocity requires an orbital eccentricity of approximately 0.95. This eccentricity is also consistent with the value inferred by matching the pericenter to the estimated wind-launching radius.

Although such an orbit is technically possible and can narrowly avoid tidal disruption for a solar-mass star, the paper leaves unresolved how an orbit with the necessary eccentricity, compactness, and pericenter distance forms.

References

Such a highly eccentric and tight orbit is technically possible, as it narrowly avoids tidal disruption for a solar-mass star, but the formation channel of such an orbit is unclear.

— Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms  (2608.28507 - Chakraborty et al., 28 Aug 2026) in Section 3.1, “Constraints on energetics, long-term evolution, and QPE models”

This picture agrees qualitatively with recent work modeling QPEs arising from the collisions of extended debris streams surrounding an EMRI orbiter with the SMBH accretion disk \citep{Linial25,Yao26b}; however, it is not yet clear whether other models (e.g. disk instabilities) are entirely unable to produce such behavior, making definitive model comparisons premature.

— Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms  (2608.28507 - Chakraborty et al., 28 Aug 2026) in Section 4, “Conclusion”