Wilson, DJ, Gaensicke, BT, Koester, D, Raddi, R, Breedt, E, Southworth, J and Parsons, SG (2014) Variable emission from a gaseous disc around a metal-polluted white dwarf. Monthly Notices of the Royal Astronomical Society, 445 (2). 1878 -1884. ISSN 1365-2966

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We present the discovery of strongly variable emission lines from a gaseous disc around the DA white dwarf SDSS J1617+1620, a star previously found to have an infrared excess indicative of a dusty debris disc formed by the tidal disruption of a rocky planetary body. Time series spectroscopy obtained during the period 2006–2014 has shown the appearance of strong double-peaked Ca II emission lines in 2008. The lines were weak, at best, during earlier observations, and monotonically faded through the remainder of our monitoring. Our observations represent unambiguous evidence for short-term variability in the debris environment of evolved planetary systems. Possible explanations for this extraordinary variability include the impact on to the dusty disc of either a single small rocky planetesimal, or of material from a highly eccentric debris tail. The increase in flux from the emission lines is sufficient that similar events could be detected in the broad-band photometry of ongoing and future large-area time domain surveys.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: circumstellar matter, stars, individual, SDSS J1617+1620, planetary systems, white dwarfs
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Faculty of Natural Sciences > School of Physical and Geographical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 14 Jul 2015 13:36
Last Modified: 15 May 2019 09:36
URI: https://eprints.keele.ac.uk/id/eprint/720

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