Particle.news
Download on the App Store

Eccentric Orbit Confirmed in Neutron Star–Black Hole Merger GW200105

A Birmingham-developed waveform model rules out a circular path with 99.5% confidence.

Overview

  • Researchers from the University of Birmingham, Universidad Autónoma de Madrid, and the Max Planck Institute report the result in The Astrophysical Journal Letters after reanalyzing GW200105.
  • The new waveform model simultaneously tests orbital eccentricity and spin-induced precession in LIGO–Virgo data, enabling a direct measurement of non-circular motion.
  • Bayesian model comparison excludes a circular orbit with 99.5% confidence for this neutron star–black hole merger.
  • Revised parameters show a remnant about 13 times the Sun’s mass, correcting earlier mass estimates that assumed a circular inspiral.
  • No compelling precession is detected, and the measured eccentricity points to a dynamical formation channel, prompting calls for improved waveform templates and targeted searches for more eccentric mergers.