Dynamics of Stellar Spin Driven by Planets Undergoing Lidov-Kozai Migration: Paths to Spin-Orbit Misalignment
Abstract
Many exoplanetary systems containing hot Jupiters (HJs) exhibit significant misalignment between the spin axes of the host stars and the orbital angular momentum axes of the planets ('spin–orbit misalignment'). High-eccentricity migration involving Lidov–Kozai oscillations of the planet's orbit induced by a distant perturber is a possible channel for producing such misaligned HJ systems. Previous works have shown that the dynamical evolution of the stellar spin axis during the high-e migration plays a dominant role in generating the observed spin–orbit misalignment. Numerical studies have also revealed various patterns of the evolution of the stellar spin axis leading to the final misalignment. Here, we develop an analytic theory to elucidate the evolution of spin–orbit misalignment during the Lidov–Kozai migration of planets in stellar binaries. Secular spin–orbit resonances play a key role in the misalignment evolution. We include the effects of short-range forces and tidal dissipation, and categorize the different possible paths to spin–orbit misalignment as a function of various physical parameters (e.g. planet mass and stellar rotation period). We identify five distinct spin–orbit evolution paths and outcomes, only two of which are capable of producing retrograde orbits. We show that these paths to misalignment and the outcomes depend only on two dimensionless parameters, which compare the stellar spin precession frequency with the rate of change of the planet's orbital axis, and the Lidov–Kozai oscillation frequency. Our analysis reveals a number of novel phenomena for the stellar spin evolution, ranging from bifurcation, adiabatic advection, to fully chaotic evolution of spin–orbit angles.
Additional Information
© 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2016 November 17. Received 2016 November 16; in original form 2016 July 13. Published: 23 November 2016. This work has been supported in part by NSF grant AST-1211061, and NASA grants NNX14AG94G and NNX14AP31G. KRA is supported by the NSF Graduate Research Fellowship Program under grant no. DGE-1144153. NIS acknowledges partial support through a Sherman Fairchild Fellowship at Caltech.Attached Files
Published - stw3018.pdf
Submitted - 1607.03937v1.pdf
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Additional details
- Eprint ID
- 72194
- Resolver ID
- CaltechAUTHORS:20161121-101338310
- AST-1211061
- NSF
- NNX14AG94G
- NASA
- NNX14AP31G
- NASA
- DGE-1144153
- NSF Graduate Research Fellowship
- Sherman Fairchild Foundation
- Created
-
2016-11-21Created from EPrint's datestamp field
- Updated
-
2021-11-11Created from EPrint's last_modified field
- Caltech groups
- TAPIR, Walter Burke Institute for Theoretical Physics