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Planet–disc evolution and the formation of Kozai–Lidov planets

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journal contribution
posted on 16.05.2016, 08:48 by Rebecca G. Martin, Stephen H. Lubow, Chris J. Nixon, Philip J. Armitage
With hydrodynamical simulations, we determine the conditions under which an initially coplanar planet–disc system that orbits a member of a misaligned binary star evolves to form a planet that undergoes Kozai–Lidov (KL) oscillations once the disc disperses. These oscillations may explain the large orbital eccentricities, as well as the large misalignments with respect to the spin of the central star, observed for some exoplanets. The planet is assumed to be massive enough to open a gap in the disc. The planet's tilt relative to the binary orbital plane is subject to two types of oscillations. The first type, present at even small inclination angles relative to the binary orbital plane, is due to the interaction of the planet with the disc and binary companion and is amplified by a secular resonance. The second type of oscillation is the KL oscillation that operates on both the planet and disc at larger binary inclination angles. We find that for a sufficiently massive disc, even a relatively low inclination planet–disc system can force a planet to an inclination above the critical KL angle, as a consequence of the first type of tilt oscillation, allowing it to undergo the second type of oscillation. We conclude that the hydrodynamical evolution of a sufficiently massive and inclined disc in a binary system broadens the range of systems that form eccentric and misaligned giant planets to include a wide range of initial misalignment angles (20° ≲ i ≲ 160°).

Funding

SHL acknowledges support from NASA grant NNX11AK61G. CN was supported by the Science and Technology Facilities Council (grant number ST/M005917/1). Research in theoretical astrophysics at Leicester is supported by an STFC Consolidated Grant. PJA acknowledges support from NASA through grant NNX13AI58G and from the NSF through grant AST 1313021.

History

Citation

Monthly Notices of the Royal Astronomical Society, 2016, 458 (4), pp. 4345-4353

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Monthly Notices of the Royal Astronomical Society

Publisher

Oxford University Press on behalf of the Royal Astronomical Society

issn

0035-8711

eissn

1365-2966

Acceptance date

05/03/2016

Copyright date

2016

Available date

16/05/2016

Publisher version

http://mnras.oxfordjournals.org/content/458/4/4345

Language

en