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Title: Fomalhaut b as a cloud of dust: Testing aspects of planet formation theory

We consider the ability of three models—impacts, captures, and collisional cascades—to account for a bright cloud of dust in Fomalhaut b. Our analysis is based on a novel approach to the power-law size distribution of solid particles central to each model. When impacts produce debris with (1) little material in the largest remnant and (2) a steep size distribution, the debris has enough cross-sectional area to match observations of Fomalhaut b. However, published numerical experiments of impacts between 100 km objects suggest this outcome is unlikely. If collisional processes maintain a steep size distribution over a broad range of particle sizes (300 μm to 10 km), Earth-mass planets can capture enough material over 1-100 Myr to produce a detectable cloud of dust. Otherwise, capture fails. When young planets are surrounded by massive clouds or disks of satellites, a collisional cascade is the simplest mechanism for dust production in Fomalhaut b. Several tests using Hubble Space Telescope or James Webb Space Telescope data—including measuring the expansion/elongation of Fomalhaut b, looking for trails of small particles along Fomalhaut b's orbit, and obtaining low resolution spectroscopy—can discriminate among these models.
Authors:
 [1] ;  [2] ;  [3]
  1. Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 1A1 (Canada)
  3. Department of Physics, University of Utah, 201 JFB, Salt Lake City, UT 84112 (United States)
Publication Date:
OSTI Identifier:
22357003
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 786; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CAPTURE; DETECTION; DISTRIBUTION; DUSTS; ELONGATION; EVOLUTION; EXPANSION; MASS; ORBITS; PARTICLE SIZE; PLANETS; RESOLUTION; SATELLITES; SOLIDS; SPACE; SPECTROSCOPY; TELESCOPES