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Kepler Observations of V447 Lyr: an Eclipsing U Gem Cataclysmic VariableWe present the results of an analysis of Kepler data covering 1.5 yr of the dwarf nova V447 Lyr. We detect eclipses of the accretion disc by the mass donating secondary star every 3.74 h which is the binary orbital period. V447 Lyr is therefore the first dwarf nova in the Kepler field to show eclipses.We also detect five long outbursts and six short outbursts showing V447 Lyr is a U Gem-type dwarf nova. We show that the orbital phase of the mid-eclipse occurs earlier during outbursts compared to quiescence and that the width of the eclipse is greater during outburst. This suggests that the bright spot is more prominent during quiescence and that the disc is larger during outburst than quiescence. This is consistent with an expansion of the outer disc radius due to the presence of high viscosity material associated with the outburst, followed by a contraction in quiescence due to the accretion of low angular momentum material. We note that the long outbursts appear to be triggered by a short outburst, which is also observed in the super-outbursts of SU UMa dwarf novae as observed using Kepler.
Document ID
20140010261
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Ramsay, Gavin
(Armagh Observatory Ireland)
Cannizzo, John K.
(Maryland Univ. Baltimore County Baltimore, MD, United States)
Howell, Steve B.
(NASA Ames Research Center Moffett Field, CA, United States)
Wood, Matt A.
(Florida Inst. of Tech. Melbourne, FL, United States)
Still, Martin
(Bay Area Environmental Research Inst. Sonoma, CA, United States)
Barclay, Thomas
(Bay Area Environmental Research Inst. Sonoma, CA, United States)
Smale, Alan
(Bay Area Environmental Research Inst. Sonoma, CA, United States)
Date Acquired
July 29, 2014
Publication Date
September 11, 2012
Publication Information
Publication: Monthly Notices of the Royal Astronomical Society
Publisher: Monthly Notices of the Royal Astronomical Society
Volume: 425
Issue: 2
ISSN: 0035-8711
Subject Category
Astronomy
Report/Patent Number
GSFC-E-DAA-TN9708
Funding Number(s)
CONTRACT_GRANT: NNG06EO90A
CONTRACT_GRANT: NNX13AB68A
CONTRACT_GRANT: NNX12AB89A
CONTRACT_GRANT: NAG5-7584
CONTRACT_GRANT: NSF AST 1109332
CONTRACT_GRANT: NAS5-26555
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
cataclysmic variable
accretion disc
dwarf novae
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