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Journal Articles Monthly Notices of the Royal Astronomical Society Year : 2013

Resolved debris discs around A stars in the Herschel DEBRIS survey

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1
Mark Booth
  • Function : Author
Grant Kennedy
Bruce Sibthorpe
  • Function : Author
Brenda C. Matthews
  • Function : Author
Mark C. Wyatt
  • Function : Author
J. J. Kavelaars
David Rodriguez
  • Function : Author
Jane S. Greaves
  • Function : Author
Alice Koning
  • Function : Author
Laura Vican
  • Function : Author
George H. Rieke
  • Function : Author
Kate Y. L. Su
  • Function : Author
Amaya Moro-Martín
  • Function : Author
Paul Kalas

Abstract

The majority of debris discs discovered so far have only been detected through infrared excess emission above stellar photospheres. While disc properties can be inferred from unresolved photometry alone under various assumptions for the physical properties of dust grains, there is a degeneracy between disc radius and dust temperature that depends on the grain size distribution and optical properties. By resolving the disc we can measure the actual location of the dust. The launch of Herschel, with an angular resolution superior to previous far-infrared telescopes, allows us to spatially resolve more discs and locate the dust directly. Here we present the nine resolved discs around A stars between 20 and 40 pc observed by the Disc Emission via a Bias-free Reconnaissance in the Infrared/Submillimetre (DEBRIS) survey. We use these data to investigate the disc radii by fitting narrow ring models to images at 70, 100 and 160 μm and by fitting blackbodies to full spectral energy distributions. We do this with the aim of finding an improved way of estimating disc radii for unresolved systems. The ratio between the resolved and blackbody radii varies between 1 and 2.5. This ratio is inversely correlated with luminosity and any remaining discrepancies are most likely explained by differences to the minimum size of grain in the size distribution or differences in composition. We find that three of the systems are well fit by a narrow ring, two systems are borderline cases and the other four likely require wider or multiple rings to fully explain the observations, reflecting the diversity of planetary systems.
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Dates and versions

insu-03617524 , version 1 (24-03-2022)

Licence

Attribution - CC BY 4.0

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Mark Booth, Grant Kennedy, Bruce Sibthorpe, Brenda C. Matthews, Mark C. Wyatt, et al.. Resolved debris discs around A stars in the Herschel DEBRIS survey. Monthly Notices of the Royal Astronomical Society, 2013, 428, pp.1263-1280. ⟨10.1093/mnras/sts117⟩. ⟨insu-03617524⟩
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