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arXiv · 2310.07575

Stability of coorbital planets around binaries

Stefan Adelbert·Anna B. T. Penzlin·Christoph M. Schäfer·Wilhelm Kley·Billy Quarles·Rafael Sfair
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Abstract

In previous hydrodynamical simulations, we found a mechanism for nearly circular binary stars, like Kepler-413, to trap two planets in a stable 1:1 resonance. Therefore, the stability of coorbital configurations becomes a relevant question for planet formation around binary stars. Here, we investigate the coorbital planet stability using a Kepler-413 analogue as example and then expanding the parameters to study general n-body stability of planet pairs in eccentric horseshoe orbits around binaries. The stability is tested by evolving the planet orbits for $10^5$ binary periods with varying initial semi-major axes and planet eccentricities. The unstable region of a single circumbinary planet is used as a comparison to the investigated coorbital configurations in this work. We confirm previous findings on the stability of single planets and find a first order linear relation between orbit eccentricity and pericentre to identify stable orbits for various binary configurations. Such a linear relation is also found for the stability of 1:1 resonant planets around binaries. Stable orbits for eccentric horseshoe configurations exist with a pericentre closer than seven binary separations and, in the case of Kepler-413, the pericentre of the first stable orbit can be approximated by $r_{c,peri} = (2.88 e_p + 2.46) a_{bin}$.

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Stefan Adelbert, Anna B. T. Penzlin, Christoph M. Schäfer, Wilhelm Kley, Billy Quarles, Rafael Sfair. 2023-10-11. Stability of coorbital planets around binaries. https://doi.org/10.1051/0004-6361%2F202244329

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