Sumin Tang et al. 2011 ApJ 738 7 doi:10.1088/0004-637X/738/1/7
Sumin Tang, Jonathan Grindlay, Edward Los, and Mathieu Servillat
Show affiliationsKU Cyg is an eclipsing binary consisting of an F-type star accreting through a large accretion disk from a K5III red giant. Here we present the discovery of a 5 year dip around 1900 found from its 100 year DASCH light curve. It showed a ~0.5 mag slow fading from 1899 to 1903 and brightened back around 1904 on a relatively shorter timescale. The light curve shape of the 1899-1904 fading-brightening event differs from the dust production and dispersion process observed in R Coronae Borealis stars, which usually has a faster fading and slower recovery, and for KU Cyg is probably related to the accretion disk surrounding the F star. The slow fading in KU Cyg is probably caused by increases in dust extinction in the disk, and the subsequent quick brightening may be due to the evaporation of dust transported inward through the disk. The extinction excess which caused the fading may arise from increased mass transfer rate in the system or from dust clump ejections from the K giant.
Issue 1 (2011 September 1)
Received 2011 May 31, accepted for publication 2011 May 31
Published 2011 August 9
Sumin Tang et al. 2011 ApJ 738 7
F. W. High et al. 2010 ApJ 723 1736
Eric Gaidos et al. 2010 ApJ 718 596
Jo Bovy et al. 2010 ApJ 711 1157
J. Aleksić et al. 2010 ApJ 710 634
Paul J. Green et al. 2010 ApJ 710 1578
Eduard Westra et al. 2010 ApJ 708 534
A. L. Wilmot-Smith et al. 2009 ApJ 704 1288
C. Güttler et al. 2009 ApJ 701 130
C. L. Reichardt et al. 2009 ApJ 701 1958