Swan, A;
Farihi, J;
Wilson, TG;
Parsons, SG;
(2020)
The dust never settles: collisional production of gas and dust in evolved planetary systems.
Monthly Notices of the Royal Astronomical Society
, 496
(4)
pp. 5233-5242.
10.1093/mnras/staa1688.
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Abstract
Multi-epoch infrared photometry from Spitzer is used to monitor circumstellar discs at white dwarfs, which are consistent with disrupted minor planets whose debris is accreted and chemically reflected by their host stars. Widespread infrared variability is found across the population of 37 stars with two or more epochs. Larger flux changes occur on longer time-scales, reaching several tens of per cent over baselines of a few years. The canonical model of a geometrically thin, optically thick disc is thus insufficient, as it cannot give rise to the observed behaviour. Optically thin dust best accounts for the variability, where collisions drive dust production and destruction. Notably, the highest infrared variations are seen in systems that show Ca II emission, supporting planetesimal collisions for all known debris discs, with the most energetic occurring in those with detected gaseous debris. The sample includes the only polluted white dwarf with a circumbinary disc, where the signal of the day–night cycle of its irradiated substellar companion appears diluted by dust emission.
| Type: | Article |
|---|---|
| Title: | The dust never settles: collisional production of gas and dust in evolved planetary systems |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/staa1688 |
| Publisher version: | https://doi.org/10.1093/mnras/staa1688 |
| 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: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, circumstellar matter, stars: individual: SDSS J155720.77+091624.6, planetary systems, white dwarfs, EXCESS INFRARED RADIATION, WHITE-DWARFS, TIDAL DISRUPTION, DEBRIS DISC, ARRAY CAMERA, BROWN DWARF, SPITZER, PHOTOMETRY, ACCRETION, FREQUENCY |
| 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-pp.ucl.ac.uk/id/eprint/10113205 |
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