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Title: SECULAR BEHAVIOR OF EXOPLANETS: SELF-CONSISTENCY AND COMPARISONS WITH THE PLANET-PLANET SCATTERING HYPOTHESIS

Journal Article · · Astronomical Journal (New York, N.Y. Online)
;  [1]; ;  [2];  [3];  [4]
  1. Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195 (United States)
  2. Virtual Planetary Laboratory, Seattle, WA 98195 (United States)
  3. Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)
  4. Google, Inc., 1600 Amphitheater Parkway, Mountain View, CA 94043 (United States)

If mutual gravitational scattering among exoplanets occurs, then it may produce unique orbital properties. For example, two-planet systems that lie near the boundary between circulation and libration of their periapses could result if planet-planet scattering ejected a former third planet quickly, leaving one planet on an eccentric orbit and the other on a circular orbit. We first improve upon previous work that examined the apsidal behavior of known multiplanet systems by doubling the sample size and including observational uncertainties. This analysis recovers previous results that demonstrated that many systems lay on the apsidal boundary between libration and circulation. We then performed over 12,000 three-dimensional N-body simulations of hypothetical three-body systems that are unstable, but stabilize to two-body systems after an ejection. Using these synthetic two-planet systems, we test the planet-planet scattering hypothesis by comparing their apsidal behavior, over a range of viewing angles, to that of the observed systems and find that they are statistically consistent regardless of the multiplicity of the observed systems. Finally, we combine our results with previous studies to show that, from the sampled cases, the most likely planetary mass function prior to planet-planet scattering follows a power law with index -1.1. We find that this pre-scattering mass function predicts a mutual inclination frequency distribution that follows an exponential function with an index between -0.06 and -0.1.

OSTI ID:
22136560
Journal Information:
Astronomical Journal (New York, N.Y. Online), Vol. 146, Issue 3; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
Country of Publication:
United States
Language:
English