New HST data and modeling reveal a massive planetesimal collision around Fomalhaut

Abstract

The apparent detection of an exoplanet orbiting Fomalhaut was announced in 2008. However, subsequent observations of Fomalhaut b raised questions about its status: Unlike other exoplanets, it is bright in the optical and nondetected in the infrared, and its orbit appears to cross the debris ring around the star without the expected gravitational perturbations. We revisit previously published data and analyze additional Hubble Space Telescope (HST) data, finding that the source is likely on a radial trajectory and has faded and become extended. Dynamical and collisional modeling of a recently produced dust cloud yields results consistent with the observations. Fomalhaut b appears to be a directly imaged catastrophic collision between two large planetesimals in an extrasolar planetary system. Similar events should be very rare in quiescent planetary systems of the age of Fomalhaut, suggesting that we are possibly witnessing the effects of gravitational stirring due to the orbital evolution of hypothetical planet(s) around the star.

12 pages, 9 figures, accepted to PNAS

References in corpus (8)

• Direct Imaging of Multiple Planets Orbiting the Star HR 8799
• Optical Images of an Exosolar Planet 25 Light Years from Earth
• The timeline of the Lunar bombardment - revisited
• Spitzer/IRAC Limits to Planetary Companions of Fomalhaut and epsilon Eridani
• High-contrast Imaging with Spitzer: Deep Observations of Vega, Fomalhaut, and epsilon Eridani
• Fomalhaut b as a Dust Cloud: Frequent Collisions within the Fomalhaut Disk
• Fomalhaut b as a Cloud of Dust: Testing Aspects of Planet Formation Theory
• Early evolution of disrupted asteroid P/2016 G1 (PANSTARRS)

Cited by in corpus (17)

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• Molecular mapping of the PDS70 system: No molecular absorption signatures from the forming planet PDS70 b
• Spin-orbit alignment of the $\beta$ Pictoris planetary system
• The search for disks or planetary objects around directly imaged companions: A candidate around DH Tau B
• Radio Observations of HD80606 Near Planetary Periastron: II. LOFAR Low Band Antenna Observations at 30-78 MHz
• Fomalhaut b could be massive and sculpting the narrow, eccentric debris disc, if in mean-motion resonance with it
• Constrained Reference Star Differential Imaging: Enabling High-Fidelity Imagery of Highly Structured Circumstellar Disks
• Efficiently Imaging Accreting Protoplanets from Space: Reference Star Differential Imaging of the PDS 70 Planetary System using the HST/WFC3 Archival PSF Library
• Extreme Variability of the V488 Persei Debris Disk
• Tidal disruption versus planetesimal collisions as possible origins for the dispersing dust cloud around Fomalhaut
• Hiding Dust Around $\epsilon$ Eridani
• Imaging of exocomets with infrared interferometry
• Multi-wavelength aperture polarimetry of debris disc host stars
• SPHERE RefPlanets: Search for epsilon Eridani b and warm dust
• Eccentric debris belts reveal the dynamical history of the companion exoplanet
• Detecting Exoplanets Using Eclipsing Binaries as Natural Starshades
• Collision rates of planetesimals near mean-motion resonances