Connecting stellar binary evolution with binary black-hole spin precession

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• Nathan Steinle
• Wednesday 26 January 2022, 14:00-15:00
• Physics West Lecture Theatre 117.

If you have a question about this talk, please contact Dr Matteo Bianconi.

The possibility of binary black holes (BBHs) that originate from isolated high-mass binary stars to experience spin precession, which modulates the emitted gravitational waves, is determined by the interplay of phenomena such as tides, winds, accretion, common-envelope evolution, natal kicks, and stellar core-envelope coupling. If isolated BBHs typically have negligible misalignments and spin magnitudes, then spin precession would be greatly suppressed. We identify regions of the parameter space that may produce BBHs with large misalignments from natal kicks and high spin magnitudes from three mechanisms – tides, accretion, or inheritance via minimal core-envelope coupling – and we explore the spin precession of such BBHs using five parameters that describe the precession and nutation of the orbital angular momentum. We find that precession is possible due to sufficiently strong natal kicks, and that nutation depends on the three spin-up mechanisms. Small spin magnitudes from maximal core-envelope coupling ensure that BBHs only precess, except when tides synchronize the spins of both binary components to allow for nutation. While accretion can, in principle, produce high spin magnitudes, it does not provide nutation as it does not occur for both binary components in the pathways that we explore. Generally, nutation is difficult to achieve without minimal core-envelope coupling, implying that a measurement of nutation from gravitational-wave observations might suggest isolated-binary origin with minimal core-envelope coupling.

This talk is part of the Astrophysics Seminars series.

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• Astrophysics Seminars
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