DDA 2015 – Dynamical Evolution of planets in α Centauri AB

This is one of a series of notes taken during the 2015 meeting of the AAS Division on Dynamical Astronomy, 3-7 May, at CalTech. An index to this series (all the papers presented at the meeting) is here.

Session: Dynamical Constraints from Exoplanet Observations I

Billy L. Quarles (NASA Ames Research Center)


Circumstellar planets within α Centauri AB have been suggested through formation models (Quintana et al. 2002) and recent observations (Demusque et al. 2012). Driven by a new mission concept that will aRempt to directly image Earth-sized planets, ACESat (Belikov et al. 2015), we revisit their possible existence through simulations of orbital stability that are far more comprehensive than were feasible by Wiegert and Holman (1997). We evaluate the stability boundary of Earth-like planets within α Centauri AB and elucidate some of the necessary observational constraints relative to the sky plane to directly image Earth-like planets orbiting either stellar component. We confirm the qualitative results of Wiegert and Holman regarding the approximate size of the regions of stable orbits and find that mean motion resonances with the stellar companion leave an imprint on the limits of orbital stability. Additionally, we discuss the differences in the extent of the imprint when considering both prograde and retrograde motions relative to the binary plane.


  • Why $\alpha$Cen?
    • solar-like stars separated by 10s of AU
    • planet formation
    • astrobiology
  • Dumusque et al,Demory et al 2015
    • 3.2-day planet, ~1.1 $M_E$
    • HST: transit observed
  • RedoofWiegert & Holman 1997 numerical sims
    • 10 Myr, 100 Myr, 1 Gyr
    • circular inclined case
    • planar eccentric case
    • stability @100Myr:
      • $a_{max} \sim 2.5$ AU

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