Consequences of an Eccentric Orbit for Fomalhaut b

Abstract

Fomalhaut b is currently the least massive, directly imaged exoplanet candidate. New observation epochs reveal this object to be moving on a highly eccentric orbit (Kalas et al. 2013), which sets important new constraints. I consider scenarios where Fomalhaut b is the only object interacting with the debris disk, and ones involving an additional unseen planet. I also investigate the possibility that Fomalhaut b is merely a transient dust cloud in light of the revised eccentric orbit. I argue that the scenario best able to match the observational constraints is a super-Earth Fomalhaut b surrounded by a vast cloud of dust that is generated by a population of irregular satellites, with an undetected $\sim$ Saturn-mass planet orbiting interior to the disk and driving the secular dynamics. Testable predictions are summarized that could differentiate between this scenario and other possibilities.

25 pages, 6 figures. Accepted for publication in MNRAS

References in corpus (3)

• Optical Images of an Exosolar Planet 25 Light Years from Earth
• Irregular Satellites of the Planets: Products of Capture in the Early Solar System
• Spitzer/IRAC Limits to Planetary Companions of Fomalhaut and epsilon Eridani

Cited by in corpus (25)

• Detection of exocometary CO within the 440 Myr-old Fomalhaut belt: a similar CO+CO${}_2$ ice abundance in exocomets and Solar System comets
• A Complete ALMA Map of the Fomalhaut Debris Disk
• Five steps in the evolution from protoplanetary to debris disk
• Dynamical evolution of an eccentric planet and a less massive debris disc
• CO mass upper limits in the Fomalhaut ring - the importance of NLTE excitation in debris discs and future prospects with ALMA
• A Machine Learns to Predict the Stability of Tightly Packed Planetary Systems
• How to design a planetary system for different scattering outcomes: giant impact sweet spot, maximising exocomets, scattered disks
• High-contrast Imaging with Spitzer: Deep Observations of Vega, Fomalhaut, and epsilon Eridani
• New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
• The Fate of Scattered Planets
• Fomalhaut b as a Dust Cloud: Frequent Collisions within the Fomalhaut Disk
• Constraining the orbits of sub-stellar companions imaged over short orbital arcs
• Fomalhaut b as a Cloud of Dust: Testing Aspects of Planet Formation Theory
• Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
• Dancing with the Stars: Formation of the Fomalhaut triple system and its effect on the debris disks
• Insights on the dynamical history of the Fomalhaut system - Investigating the Fom c hypothesis
• Extrasolar Kuiper Belts
• Searching for the near infrared counterpart of Proxima c using multi-epoch high contrast SPHERE data at VLT
• Simulations of the Fomalhaut System Within Its Local Galactic Environment
• Debris Disks: Probing Planet Formation
• ALMA imaging of the M-dwarf Fomalhaut C's debris disc
• Constraints on the gas content of the Fomalhaut debris belt. Can gas-dust interactions explain the belt's morphology?
• Collisional Cascade Caclulations for Irregular Satellite Swarms in Fomalhaut b
• The impact of initial conditions in N-body simulations of debris discs
• Numerical search for a potential planet sculpting the young disc of HD 115600