Kirchschlager, F;
Wolf, S;
Krivov, AV;
Mutschke, H;
Brunngraeber, R;
(2017)
Constraints on the structure of hot exozodiacal dust belts.
Monthly Notices of the Royal Astronomical Society
, 467
(2)
pp. 1614-1626.
10.1093/mnras/stx202.
Preview |
Text
Kirchschlager_Constraints on the structure of hot exozodiacal dust belts_VoR.pdf - Published Version Download (1MB) | Preview |
Abstract
Recent interferometric surveys of nearby main-sequence stars show a faint but significant near-infrared excess in roughly two dozen systems, i.e. around 10–30 per cent of stars surveyed. This excess is attributed to dust located in the immediate vicinity of the star, the origin of which is highly debated. We used previously published interferometric observations to constrain the properties and distribution of this hot dust. Considering both scattered radiation and thermal re-emission, we modelled the observed excess in nine of these systems. We find that grains have to be sufficiently absorbing to be consistent with the observed excess, while dielectric grains with pure silicate compositions fail to reproduce the observations. The dust should be located within ∼0.01–1 au from the star depending on its luminosity. Furthermore, we find a significant trend for the disc radius to increase with the stellar luminosity. The dust grains are determined to be below 0.2--0.5μm, but above 0.02--0.15μm in radius. The dust masses amount to (0.2–3.5) × 10⁻⁹ M⊕. The near-infrared excess is probably dominated by thermal re-emission, though a contribution of scattered light up to 35 per cent cannot be completely excluded. The polarization degree predicted by our models is always below 5 per cent, and for grains smaller than ∼0.2μm even below 1 per cent. We also modelled the observed near-infrared excess of another 10 systems with poorer data in the mid-infrared. The basic results for these systems appear qualitatively similar, yet the constraints on the dust location and the grain sizes are weaker.
| Type: | Article |
|---|---|
| Title: | Constraints on the structure of hot exozodiacal dust belts |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stx202 |
| Publisher version: | https://doi.org/10.1093/mnras/stx202 |
| Language: | English |
| Additional information: | This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | techniques: interferometric, interplanetary medium, planets and satellites: fundamental parameters, zodiacal dust, circumstellar matter, infrared: planetary systems |
| 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/10022713 |
Archive Staff Only
 |
View Item |
