Orbital evolution of a circumbinary planet in a gaseous disk

Abstract Sub-Jupiter classed circumbinary planets discovered in close-in binary systems have orbits just beyond the dynamically unstable region, which is determined by the eccentricity and mass ratio of the host binary stars. These planets are assumed to have formed beyond the snow line and migrated...

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Main Authors: Akihiro Yamanaka, Takanori Sasaki
Format: Article
Language:English
Published: SpringerOpen 2019-07-01
Series:Earth, Planets and Space
Subjects:
Online Access:http://link.springer.com/article/10.1186/s40623-019-1064-0
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author Akihiro Yamanaka
Takanori Sasaki
author_facet Akihiro Yamanaka
Takanori Sasaki
author_sort Akihiro Yamanaka
collection DOAJ
description Abstract Sub-Jupiter classed circumbinary planets discovered in close-in binary systems have orbits just beyond the dynamically unstable region, which is determined by the eccentricity and mass ratio of the host binary stars. These planets are assumed to have formed beyond the snow line and migrated to the current orbits rather than forming in situ. We propose a scenario in which a planet formed beyond the snow line and migrated to the inner edge of the circumbinary disk, which was within the unstable area, and then moved to the current orbit through outward transportation. This outward transportation is driven by the balance of orbital excitation of the central stars inside the gravitationally unstable region and damping by the gas-drag force. We carried out N-body simulations with a dissipating circumbinary protoplanetary disk for binary systems with different eccentricities and mass ratios. Planets are more likely to achieve a stable orbit just beyond the unstable region in less eccentric binary systems. This result is not as sensitive to mass ratio as it is to eccentricity. These dependencies are consistent with the data from observed binary systems hosting circumbinary planets. We find CBPs’ orbits close to the instability boundaries are explained by our orbital evolution scenario.
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spelling doaj.art-a9c07ec13f1b4947b7e83f13c3f85c2e2022-12-22T01:13:30ZengSpringerOpenEarth, Planets and Space1880-59812019-07-0171111210.1186/s40623-019-1064-0Orbital evolution of a circumbinary planet in a gaseous diskAkihiro Yamanaka0Takanori Sasaki1Department of Astronomy, Kyoto UniversityDepartment of Astronomy, Kyoto UniversityAbstract Sub-Jupiter classed circumbinary planets discovered in close-in binary systems have orbits just beyond the dynamically unstable region, which is determined by the eccentricity and mass ratio of the host binary stars. These planets are assumed to have formed beyond the snow line and migrated to the current orbits rather than forming in situ. We propose a scenario in which a planet formed beyond the snow line and migrated to the inner edge of the circumbinary disk, which was within the unstable area, and then moved to the current orbit through outward transportation. This outward transportation is driven by the balance of orbital excitation of the central stars inside the gravitationally unstable region and damping by the gas-drag force. We carried out N-body simulations with a dissipating circumbinary protoplanetary disk for binary systems with different eccentricities and mass ratios. Planets are more likely to achieve a stable orbit just beyond the unstable region in less eccentric binary systems. This result is not as sensitive to mass ratio as it is to eccentricity. These dependencies are consistent with the data from observed binary systems hosting circumbinary planets. We find CBPs’ orbits close to the instability boundaries are explained by our orbital evolution scenario.http://link.springer.com/article/10.1186/s40623-019-1064-0Planets and satellites: dynamical evolution and stabilityPlanets and satellites: formationPlanet–disk interactions
spellingShingle Akihiro Yamanaka
Takanori Sasaki
Orbital evolution of a circumbinary planet in a gaseous disk
Earth, Planets and Space
Planets and satellites: dynamical evolution and stability
Planets and satellites: formation
Planet–disk interactions
title Orbital evolution of a circumbinary planet in a gaseous disk
title_full Orbital evolution of a circumbinary planet in a gaseous disk
title_fullStr Orbital evolution of a circumbinary planet in a gaseous disk
title_full_unstemmed Orbital evolution of a circumbinary planet in a gaseous disk
title_short Orbital evolution of a circumbinary planet in a gaseous disk
title_sort orbital evolution of a circumbinary planet in a gaseous disk
topic Planets and satellites: dynamical evolution and stability
Planets and satellites: formation
Planet–disk interactions
url http://link.springer.com/article/10.1186/s40623-019-1064-0
work_keys_str_mv AT akihiroyamanaka orbitalevolutionofacircumbinaryplanetinagaseousdisk
AT takanorisasaki orbitalevolutionofacircumbinaryplanetinagaseousdisk