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Title: Resolved multifrequency radio observations of GG Tau

We present subarcsecond resolution observations of continuum emission associated with the GG Tau quadruple star system at wavelengths of 1.3, 2.8, 7.3, and 50 mm. These data confirm that the GG Tau A binary is encircled by a circumbinary ring at a radius of 235 AU with a FWHM width of ∼60 AU. We find no clear evidence for a radial gradient in the spectral shape of the ring, suggesting that the particle size distribution is spatially homogeneous on angular scales ≳0.''1. A central point source, likely associated with the primary component (GG Tau Aa), exhibits a composite spectrum from dust and free-free emission. Faint emission at 7.3 mm is observed toward the low-mass star GG Tau Ba, although its origin remains uncertain. Using these measurements of the resolved, multifrequency emission structure of the GG Tau A system, models of the far-infrared to radio spectrum are developed to place constraints on the grain size distribution and dust mass in the circumbinary ring. The non-negligible curvature present in the ring spectrum implies a maximum particle size of 1-10 mm, although we are unable to place strong constraints on the distribution shape. The corresponding dust mass is 30-300 M {sub ⊕}, atmore » a temperature of 20-30 K. We discuss how this significant concentration of relatively large particles in a narrow ring at a large radius might be produced in a local region of higher gas pressures (i.e., a particle 'trap') located near the inner edge of the circumbinary disk.« less
Authors:
; ; ;  [1] ; ;  [2] ; ; ;  [3] ;  [4] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ; ;  [10] ;  [11] ;  [12] ;  [13] more »; « less
  1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  2. National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States)
  3. California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)
  4. Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
  5. Joint ALMA Observatory, Avenida Alonso de Córdova 3107, Vitacura, Santiago (Chile)
  6. The Netherlands Institute for Radio Astronomy (ASTRON), 7990-AA Dwingeloo (Netherlands)
  7. Heidelberg University, Center for Astronomy, Albert Ueberle Str 2, D-69120 Heidelberg (Germany)
  8. University of St. Andrews, Physics and Astronomy, North Haugh, St. Andrews KY16 9SS (United Kingdom)
  9. Department of Astronony, University of Illinois, Urbana, IL 61810 (United States)
  10. Max Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
  11. SRON Netherlands Institute for Space Research, Landleven 12, 9747 AD Groningen (Netherlands)
  12. Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91106 (United States)
  13. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
Publication Date:
OSTI Identifier:
22356764
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 787; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; CONCENTRATION RATIO; DISTRIBUTION; DUSTS; EMISSION; GRAIN SIZE; LIMITING VALUES; MASS; PARTICLE SIZE; POINT SOURCES; PROTOPLANETS; RESOLUTION; SPECTRA; STARS; TRAPS; WAVELENGTHS