Planet-Planet Scattering Leads to Tightly Packed Planetary Systems.
Venue
The Astrophysical Journal, Letters, vol. 696 (2011), pp. 98-101
Publication Year
2011
Authors
Sean N. Raymond, Rory Barnes, Dimitri Veras, Philip J. Armitage, Noel Gorelick, Richard Greenberg
BibTeX
Abstract
The known extrasolar multiple-planet systems share a surprising dynamical
attribute: they cluster just beyond the Hill stability boundary. Here we show that
the planet-planet scattering model, which naturally explains the observed exoplanet
eccentricity distribution, can reproduce the observed distribution of dynamical
configurations. We calculated how each of our scattered systems would appear over
an appropriate range of viewing geometries; as Hill stability is weakly dependent
on the masses, the mass-inclination degeneracy does not significantly affect our
results. We consider a wide range of initial planetary mass distributions and find
that some are poor fits to the observed systems. In fact, many of our scattering
experiments overproduce systems very close to the stability boundary. The
distribution of dynamical configurations of two-planet systems actually may provide
better discrimination between scattering models than the distribution of
eccentricity. Our results imply that, at least in their inner regions which are
weakly affected by gas or planetesimal disks, planetary systems should be "packed",
with no large gaps between planets.
