Effects of Proxima Centauri on Planet Formation in Alpha Centauri

Abstract

Proxima Centauri is an M dwarf approximately 15,000 AU from the Alpha Centauri binary, comoving and likely in a loosely bound orbit. Dynamic simulations show this configuration can form from a more tightly bound triple system. As our nearest neighbors, these stars command great interest as potential planet hosts, and the dynamics of the stars govern the formation of any planets within the system. Here we present a scenario for the evolution of Alpha Centauri A and B and Proxima Centauri as a triple system. Based on N-body simulations, we determine this pathway to formation is plausible, and we quantify the implications for planet formation in the Alpha Centauri binary. We expect this formation scenario may have truncated the circumstellar disk slightly more than a system that formed in the current configuration, but that it most likely does not prevent terrestrial planet formation. We simulate planet formation in this system and find that in most scenarios, two or more terrestrial planets can be expected around either Alpha Centauri A or B, orbiting in a region out to approximately 2 AU, assuming planetesimals and planetary embryos are able to first form in the system. Additionally, terrestrial planet formation and stability in Proxima Centauri's habitable zone is also plausible. However, an absence of planets around these stars may be indicative of highly disruptive stellar dynamics in the past.

Accepted to ApJ on Aug. 19th, 2016

References in corpus (39)

• Habitable Zones Around Main-Sequence Stars: New Estimates
• Long-Term Stability of Planets in Binary Systems
• Architecture of Kepler's Multi-transiting Systems: II. New investigations with twice as many candidates
• Habitable Zones Around Main-Sequence Stars: Dependence on Planetary Mass
• The Discovery of a Planetary Companion to 16 Cygni B
• The Minimum-Mass Extrasolar Nebula: In-Situ Formation of Close-In Super-Earths
• Collisions Between Gravity-Dominated Bodies: 1. Outcome Regimes and Scaling Laws
• Collisions between Gravity-Dominated Bodies: 2. The Diversity of Impact Outcomes during the End Stage of Planet Formation
• Five Planets Orbiting 55 Cancri
• Inside-Out Planet Formation
• Formation of the Widest Binaries from Dynamical Unfolding of Triple Systems
• Ghost in the time series: no planet for Alpha Cen B
• No universal minimum-mass extrasolar nebula: Evidence against in-situ accretion of systems of hot super-Earths
• Terrestrial Planet Formation Around Individual Stars Within Binary Star Systems
• Constraining the difference in convective blueshift between the components of alpha Cen with precise radial velocities
• Radial Velocity Detection of Earth-mass Planets in the Presence of Activity Noise: The Case of Alpha Centauri Bb
• The Stability of Planets in the Alpha Centauri system
• Circumstellar disks in binary star systems
• Cross Sections for Planetary Systems Interacting with Passing Stars and Binaries
• The multiplicity of exoplanet host stars - New low-mass stellar companions of the exoplanet host stars HD125612 and HD212301
• Planet formation in Alpha Centauri A revisited: not so accretion-friendly after all
• Formation and Detectability of Terrestrial Planets Around Alpha Centauri B
• Planetesimal Accretion in Binary Systems: Could Planets Form Around Alpha Centauri B ?
• On the Likelihood of Planet Formation in Close Binaries
• Planet formation in stellar binaries II: overcoming the fragmentation barrier in alpha Centauri and gamma Cephei-like systems
• Planet formation in stellar binaries I: planetesimal dynamics in massive protoplanetary disks
• Planet formation in the habitable zone of alpha Centauri B
• Seeding Life on the Moons of the Outer Planets via Lithopanspermia
• Are Proxima and Alpha Centauri Gravitationally Bound?
• Orphaned Protostars
• Disk Truncation and Planet Formation in gamma Cephei
• Formation of terrestrial planets in close binary systems: the case of Alpha Centauri A
• Exoplanets Beyond the Solar Neighbourhood: Galactic Tidal Perturbations
• Hubble Space Telescope search for the transit of the Earth-mass exoplanet Alpha Centauri Bb
• Constraints on the Formation of the Planet Around HD188753A
• Detectability of Earth-like Planets in Circumstellar Habitable Zones of Binary Star Systems with Sun-like Components
• Oscillations in the Habitable Zone around Alpha Centauri B
• The Mt John University Observatory Search For Earth-mass Planets In The Habitable Zone Of Alpha Centauri
• Outward Migration of Terrestrial Embryos in Binary Systems

Cited by in corpus (6)

• Proxima's orbit around Alpha Centauri
• The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present
• The radii and limb darkenings of Alpha Centauri A and B - Interferometric measurements with VLTI/PIONIER
• Long-Term Stability of Tightly Packed Multi-Planet Systems in Prograde, Coplanar, Circumstellar Orbits within the $\alpha$ Centauri AB System
• The chemical composition of $\alpha$ Cen AB revisited
• Evolution of $\alpha$ Centauri B's protoplanetary disc