Swan, A., Farihi, J., Wilson, T.G. et al. (1 more author) (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. ISSN 0035-8711
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.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2020 The Author(s). Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | circumstellar matter; stars: individual: SDSS J155720.77+091624.6; planetary systems; white dwarfs |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) |
Funding Information: | Funder Grant number SCIENCE AND TECHNOLOGY FACILITIES COUNCIL ST/R003424/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 21 Jul 2020 16:40 |
Last Modified: | 21 Jul 2020 16:40 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/staa1688 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:163556 |