A new waveform model, SEOBNRv6EHM, has been developed to more accurately analyze gravitational waves from eccentric compact binaries. Orbital eccentricity is a key indicator of the formation channels and astrophysical environments of these systems, making its correct inference crucial. This advancement overcomes the limitations of previous models such as SEOBNRv5EHM and TEOBResumS-Dalí, which showed biases in estimating eccentricity, masses, and spins in complex configurations.

The research team applied SEOBNRv6EHM to 26 gravitational wave events detected by the LIGO-Virgo-KAGRA collaboration during their O1-O4 observing runs, including binary black hole mergers, neutron star-black hole systems, and binary neutron stars. They identified five events with moderate support for eccentricity over the quasi-circular precessing spin hypothesis, with Bayes factors $\log_{10} \mathcal{B}^{\text{EAS}}_{\text{QCP}} > 0.5$. Furthermore, the model is applicable to generic planar binaries, allowing for the re-analysis of five high-mass events under the consideration of unbound initial conditions.

For three of these events, including GW190521 (previously suggested as a dynamical capture), a direct capture configuration was found to be comparable or marginally favored over the eccentric aligned-spin and quasi-circular precessing-spin hypotheses, with Bayes factors $\log_{10}\mathcal{B}^{\rm unbound}_{\rm QCP} \approx 0.2-0.6$ for GW190521. However, the recovered configurations are not astrophysically realistic and cannot be confidently distinguished from highly eccentric bound orbits, thus these results do not confirm an unbound origin. SEOBNRv6EHM is approximately three times faster in parameter estimation analyses than its predecessor, SEOBNRv5EHM, while also improving waveform accuracy, facilitating efficient and large-scale inferences with eccentric waveforms.