Fomalhaut b as a Dust Cloud: Frequent Collisions within the Fomalhaut Disk
arXiv:1412.1129 · doi:10.1088/2041-8205/802/2/L20
Abstract
The planet candidate Fomalhaut b is bright in optical light but undetected in longer wavelengths, requiring a large, reflective dust cloud. The most recent observations find an extremely eccentric orbit (e ~ 0.8), indicating that Fomalhaut b cannot be the planet that is constraining the system's eccentric debris ring. An irregular satellite swarm around a super-Earth has been proposed, however, explaining the well-constrained debris ring requires an additional planet on an orbit that crosses that of the putative super-Earth. This paper expands upon a second theory: Fomalhaut b is a transient dust cloud produced by a catastrophic collision between planetesimals in the disk. We perform collisional probability simulations of the Fomalhaut debris disk based on the structure of our Kuiper belt, finding that the catastrophic disruption rate of d ~ 100 km bodies in the high-eccentricity scattering component is several per decade. This model paints a picture of the Fomalhaut system as having recently (within ~10-100 Myr) experienced a dynamical instability within its planetary system, which scattered a massive number of planetesimals onto large, high eccentricity orbits similar to that of Fom b. If Fomalhaut b is indeed a dust cloud produced by such a collision, we should soon see another appear, while Fomalhaut b will expand until it is either resolved or becomes too faint to be seen.
accepted to ApJL
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- Spatially resolved imaging of the inner Fomalhaut disk using JWST/MIRI
- New HST data and modeling reveal a massive planetesimal collision around Fomalhaut
- Constraining the orbits of sub-stellar companions imaged over short orbital arcs
- The search for disks or planetary objects around directly imaged companions: A candidate around DH Tau B
- Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
- Clearing residual planetesimals by sweeping secular resonances in transitional disks: a lone-planet scenario for the wide gaps in debris disks around Vega and Fomalhaut
- Extrasolar Kuiper Belts
- The far reaches of the beta Pictoris debris disk
- Revealing asymmetrical dust distribution in the inner regions of HD 141569
- 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
- Tidal disruption versus planetesimal collisions as possible origins for the dispersing dust cloud around Fomalhaut
- ALMA imaging of the M-dwarf Fomalhaut C's debris disc
- On the Origin of Banded Structure in Dusty Protoplanetary Discs: HL Tau and TW Hya
- An Early Catalog of Planet Hosting Multiple Star Systems of Order Three and Higher
- Imaging of exocomets with infrared interferometry
- 94 Ceti: a triple star with a planet and dust disc
- Searching for Planets Orbiting Vega with the James Webb Space Telescope
- High Resolution ALMA Data of the Fomalhaut Debris Disk Confirms Apsidal Width Variation
- A second planetesimal collision in the Fomalhaut system