Dynamical Simulations of the Planetary System HD69830

Abstract

HD 69830 exhibits radial velocity variations attributed to three planets as well as infrared emission attributed to a warm debris disk. Previous studies have developed models for the planet migration and mass growth (Alibert et al. 2006) and the replenishment of warm grains (Wyatt et al. 2007). We perform n-body integrations in order to explore the implications of these models for: 1) the excitation of planetary eccentricity, 2) the accretion and clearing of a putative planetesimal disk, 3) the distribution of planetesimal orbits following migration, and 4) the implications for the origin of the IR emission. We find that: i) It is not possible to explain the observed planetary eccentricities (e~0.1) purely as the result of planetary perturbations during migration unless the planetary system is nearly face-on. ii) The rate of accretion of planetesimals onto planets in our n-body simulations is significantly different to that assumed in the semi-analytic models, suggesting that one cannot successfully treat planetesimal accretion in the simplified manner of Alibert et al. (2006). iii) Eccentricity damping of planetesimals does not act as an insurmountable obstacle to the existence of an excited eccentric disk: All simulations result in at least 25 Earth-masses of material remaining bound in the region ~1-9 AU, even after all three planets have migrated through the region. iv) Gas drag works to size-sort the planetesimals, with the largest bodies preferentially occupying the highest eccentricity and longest-lived orbits. Further work will be required to understand whether these eccentricity distributions are high enough to explain the level of dust emission observed despite mass loss via steady state collisional evolution. [abridged]

16 pages, 10 figures, accepted for publication in MNRAS

References in corpus (13)

• Dynamical Outcomes of Planet-Planet Scattering
• Origins of Eccentric Extrasolar Planets: Testing the Planet-Planet Scattering Model
• Toward a Deterministic Model of Planetary Formation V. Accumulation Near the Ice Line
• Transience of hot dust around sun-like stars
• Long-Term Collisional Evolution of Debris Disks
• Post-Oligarchic Evolution of Protoplanetary Embryos and the Stability of Planetary Systems
• Evidence for Planet-Planet Scattering in Upsilon Andromedae
• On the Nature of the Dust in the Debris Disk Around HD69830
• On the formation of terrestrial planets in hot-Jupiter systems
• Formation and accretion history of terrestrial planets from runaway growth through to late time: implications for orbital eccentricity
• The effect of type I migration on the formation of terrestrial planets in hot-Jupiter systems
• The Secular Evolution and Dynamical Architecture of the Neptunian Triplet Planetary System HD 69830
• Oligarchic planetesimal accretion and giant planet formation