Orbital evolution of potentially habitable planets of tidally interacting binary stars

Graham, David E.; Fleming, D. P.; Barnes, Rory

doi:10.1051/0004-6361/202038940

Cited by 1 publication

(1 citation statement)

References 59 publications

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“…However, the planet-hosting Kepler binary systems are close binaries that in addition to the disc impact are influenced by tidal interactions between the stars. In a theoretical study of Kepler 47b (Graham et al 2021), the binary stars have roughly a semimajor axis change of 0.5% over 10 9 years. This would be a much slower change than the effect we see from the disc.…”

Section: Discussionmentioning

confidence: 99%

Binary orbital evolution driven by a circumbinary disc

Penzlin

Kley

Audiffren

et al. 2022

A&A

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The question whether the interaction of a circumbinary disc with the central binary system leads to a shrinking or to an expansion of the binary orbit has attracted considerable interest as it impacts the evolution of binary black holes and stellar binary stars in their formation phase. We performed two-dimensional hydrodynamical simulations of circumbinary discs for a large parameter set of disc viscosities and thicknesses and for two different binary mass ratios for binaries on circular orbits. We measured the net angular momentum and mass transfer between disc and binary system, and evaluated the normalised specific angular momentum accretion, js. This was compared to the theoretical, critical specific angular momentum change js,crit that separates contracting from expanding cases, which depends on the binary mass ratio and on the relative accretion onto the two stars. Using finite and infinite disc models, we show that the inferred binary evolution is very similar for both setups, and we confirm that js can be measured accurately with cylindrical simulations that do not include the central binary. However, to obtain the relative accretion onto the stars for non-equal mass binaries, simulations that cover the whole domain including the binary are required. We find that for thick discs with aspect ratio h = 0.1, the binaries expand for all viscosities, while discs with h = 0.05 lead to an expansion only for higher viscosities with α exceeding ∼0.005. Overall, the regime of binary expansion extends to a much wider parameter space than previously anticipated, but for thin, low-viscosity discs, the orbits shrink.

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Section: Discussionmentioning

confidence: 99%