Spin-orbit Misalignment as a Driver of the Kepler Dichotomy
- Creators
- Spalding, Christopher
- Batygin, Konstantin
Abstract
During its five-year mission, the Kepler spacecraft has uncovered a diverse population of planetary systems with orbital configurations ranging from single-transiting planets to systems of multiple planets co-transiting the parent star. By comparing the relative occurrences of multiple to single-transiting systems, recent analyses have revealed a significant over-abundance of singles. Dubbed the "Kepler Dichotomy," this feature has been interpreted as evidence for two separate populations of planetary systems: one where all orbits are confined to a single plane, and a second where the constituent planetary orbits possess significant mutual inclinations, allowing only a single member to be observed in transit at a given epoch. In this work, we demonstrate that stellar obliquity, excited within the disk-hosting stage, can explain this dichotomy. Young stars rotate rapidly, generating a significant quadrupole moment, which torques the planetary orbits, with inner planets influenced more strongly. Given nominal parameters, this torque is sufficiently strong to excite significant mutual inclinations between planets, enhancing the number of single-transiting planets, sometimes through a dynamical instability. Furthermore, as hot stars appear to possess systematically higher obliquities, we predict that single-transiting systems should be relatively more prevalent around more massive stars. We analyze the Kepler data and confirm this signal to be present.
Additional Information
© 2016 American Astronomical Society. Received 2016 June 6; revised 2016 July 12; accepted 2016 July 14; published 2016 September 30. This research is based in part upon work supported by NSF grant AST 1517936 and the NESSF Graduate Fellowship in Earth and Planetary Sciences (C.S). We would like to thank Erik Petigura, Henry Ngo, and Peter Gao for helpful discussions, along with Fred Adams and Joe O'Rourke for useful suggestions. We are grateful to the anonymous reviewer for helpful comments that significantly improved the manuscript.Attached Files
Published - apj_830_1_5.pdf
Submitted - 1607.03999v1.pdf
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Additional details
- Eprint ID
- 70740
- Resolver ID
- CaltechAUTHORS:20161003-082759412
- AST-1517936
- NSF
- NASA Earth and Space Science Fellowship
- Created
-
2016-10-03Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences