Brunngraeber, R;
Wolf, S;
Kirchschlager, F;
Ertel, S;
(2017)
The influence of dust grain porosity on the analysis of debris disc observations.
Monthly Notices of the Royal Astronomical Society
, 464
(4)
pp. 4383-4389.
10.1093/mnras/stw2675.
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Abstract
Debris discs are often modelled assuming compact dust grains, but more and more evidence for the presence of porous grains is found. We aim at quantifying the systematic errors introduced when modelling debris discs composed of porous dust with a disc model assuming spherical, compact grains. We calculate the optical dust properties derived via the fast, but simple effective medium theory. The theoretical lower boundary of the size distribution – the so-called ‘blowout size’ – is compared in the cases of compact and porous grains. Finally, we simulate observations of hypothetical debris discs with different porosities and feed them into a fitting procedure using only compact grains. The deviations of the results for compact grains from the original model based on porous grains are analysed. We find that the blowout size increases with increasing grain porosity up to a factor of 2. An analytical approximation function for the blowout size as a function of porosity and stellar luminosity is derived. The analysis of the geometrical disc set-up, when constrained by radial profiles, is barely affected by the porosity. However, the determined minimum grain size and the slope of the grain size distribution derived using compact grains are significantly overestimated. Thus, the unexpectedly high ratio of minimum grain size to blowout size found by previous studies using compact grains can be partially described by dust grain porosity, although the effect is not strong enough to completely explain the trend.
| Type: | Article |
|---|---|
| Title: | The influence of dust grain porosity on the analysis of debris disc observations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stw2675 |
| Publisher version: | http://doi.org/10.1093/mnras/stw2675 |
| Language: | English |
| Additional information: | © 2016 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, interplanetary medium, circumstellar matter, infrared: stars, CIRCUMSTELLAR DISK, RADIATION PRESSURE, INFRARED-EMISSION, SMALL PARTICLES, SOLAR-SYSTEM, KUIPER-BELT, HIP 17439, SCATTERING, SPACE, HERSCHEL/DUNES |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10022800 |
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