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Title: CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?

Abstract

The planet candidates discovered by the Kepler mission provide a rich sample to constrain the architectures and relative inclinations of planetary systems within approximately 0.5 AU of their host stars. We use the triple-transit systems from the Kepler 16 months data as templates for physical triple-planet systems and perform synthetic transit observations, varying the internal inclination variation of the orbits. We find that all the Kepler triple-transit and double-transit systems can be produced from the triple-planet templates, given a low mutual inclination of around 5 Degree-Sign . Our analysis shows that the Kepler data contain a population of planets larger than four Earth radii in single-transit systems that cannot arise from the triple-planet templates. We explore the hypothesis that high-mass counterparts of the triple-transit systems underwent dynamical instability to produce a population of massive double-planet systems of moderately high mutual inclination. We perform N-body simulations of mass-boosted triple-planet systems and observe how the systems heat up and lose planets by planet-planet collisions, and less frequently by ejections or collisions with the star, yielding transits in agreement with the large planets in the Kepler single-transit systems. The resulting population of massive double-planet systems nevertheless cannot explain the additional excess of low-massmore » planets among the observed single-transit systems and the lack of gas-giant planets in double-transit and triple-transit systems. Planetary instability of systems of triple gas-giant planets can be behind part of the dichotomy between systems hosting one or more small planets and those hosting a single giant planet. The main part of the dichotomy, however, is more likely to have arisen already during planet formation when the formation, migration, or scattering of a massive planet, triggered above a threshold metallicity, suppressed the formation of other planets in sub-AU orbits.« less

Authors:
; ; ;  [1]
  1. Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, SE-221 00 Lund (Sweden)
Publication Date:
OSTI Identifier:
22092097
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 758; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; COMPUTERIZED SIMULATION; HYPOTHESIS; INCLINATION; INSTABILITY; MASS; ORBITS; PLANETS; PROTOPLANETS; SATELLITES; SCATTERING; STABILITY; STARS; VARIATIONS

Citation Formats

Johansen, Anders, Davies, Melvyn B., Church, Ross P., and Holmelin, Viktor. CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?. United States: N. p., 2012. Web. doi:10.1088/0004-637X/758/1/39.
Johansen, Anders, Davies, Melvyn B., Church, Ross P., & Holmelin, Viktor. CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?. United States. https://doi.org/10.1088/0004-637X/758/1/39
Johansen, Anders, Davies, Melvyn B., Church, Ross P., and Holmelin, Viktor. 2012. "CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?". United States. https://doi.org/10.1088/0004-637X/758/1/39.
@article{osti_22092097,
title = {CAN PLANETARY INSTABILITY EXPLAIN THE KEPLER DICHOTOMY?},
author = {Johansen, Anders and Davies, Melvyn B. and Church, Ross P. and Holmelin, Viktor},
abstractNote = {The planet candidates discovered by the Kepler mission provide a rich sample to constrain the architectures and relative inclinations of planetary systems within approximately 0.5 AU of their host stars. We use the triple-transit systems from the Kepler 16 months data as templates for physical triple-planet systems and perform synthetic transit observations, varying the internal inclination variation of the orbits. We find that all the Kepler triple-transit and double-transit systems can be produced from the triple-planet templates, given a low mutual inclination of around 5 Degree-Sign . Our analysis shows that the Kepler data contain a population of planets larger than four Earth radii in single-transit systems that cannot arise from the triple-planet templates. We explore the hypothesis that high-mass counterparts of the triple-transit systems underwent dynamical instability to produce a population of massive double-planet systems of moderately high mutual inclination. We perform N-body simulations of mass-boosted triple-planet systems and observe how the systems heat up and lose planets by planet-planet collisions, and less frequently by ejections or collisions with the star, yielding transits in agreement with the large planets in the Kepler single-transit systems. The resulting population of massive double-planet systems nevertheless cannot explain the additional excess of low-mass planets among the observed single-transit systems and the lack of gas-giant planets in double-transit and triple-transit systems. Planetary instability of systems of triple gas-giant planets can be behind part of the dichotomy between systems hosting one or more small planets and those hosting a single giant planet. The main part of the dichotomy, however, is more likely to have arisen already during planet formation when the formation, migration, or scattering of a massive planet, triggered above a threshold metallicity, suppressed the formation of other planets in sub-AU orbits.},
doi = {10.1088/0004-637X/758/1/39},
url = {https://www.osti.gov/biblio/22092097}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 758,
place = {United States},
year = {2012},
month = {10}
}