Han, Y., Tuthill, P.G., Lau, R.M. et al. (6 more authors) (2020) The extreme colliding-wind system Apep : resolved imagery of the central binary and dust plume in the infrared. Monthly Notices of the Royal Astronomical Society, 498 (4). pp. 5604-5619. ISSN 0035-8711
Abstract
The recent discovery of a spectacular dust plume in the system 2XMM J160050.7–514245 (referred to as ‘Apep’) suggested a physical origin in a colliding-wind binary by way of the ‘Pinwheel’ mechanism. Observational data pointed to a hierarchical triple-star system, however, several extreme and unexpected physical properties seem to defy the established physics of such objects. Most notably, a stark discrepancy was found in the observed outflow speed of the gas as measured spectroscopically in the line-of-sight direction compared to the proper motion expansion of the dust in the sky plane. This enigmatic behaviour arises at the wind base within the central Wolf–Rayet binary: a system that has so far remained spatially unresolved. Here, we present an updated proper motion study deriving the expansion speed of Apep’s dust plume over a 2-year baseline that is four times slower than the spectroscopic wind speed, confirming and strengthening the previous finding. We also present the results from high angular resolution near-infrared imaging studies of the heart of the system, revealing a close binary with properties matching a Wolf–Rayet colliding-wind system. Based on these new observational constraints, an improved geometric model is presented yielding a close match to the data, constraining the orbital parameters of the Wolf–Rayet binary and lending further support to the anisotropic wind model.
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: | techniques: high angular resolution; stars: individual: Apep; stars: Wolf–Rayet |
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) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 16 Oct 2020 09:04 |
Last Modified: | 16 Oct 2020 09:04 |
Status: | Published |
Publisher: | Oxford University Press (OUP) |
Refereed: | Yes |
Identification Number: | 10.1093/mnras/staa2349 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:166781 |