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arXiv · 1207.1222

Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra

Gavin Ramsay·Peter J. Wheatley·Simon Rosen·Thomas Barclay·Danny Steeghs
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Abstract

KL Dra is a helium accreting AM CVn binary system with an orbital period close to 25 mins. Approximately every 60 days there is a 4 mag optical outburst lasting ~10 days. We present the most sensitive X-ray observations made of an AM CVn system during an outburst cycle. A series of eight observations were made using XMM-Newton which started shortly after the onset of an optical outburst. We find that X-rays are suppressed during the optical outburst. There is some evidence for a spectral evolution of the X-ray spectrum during the course of the outburst. A periodic modulation is seen in the UV data at three epochs -- this is a signature of the binary orbital or the super-hump period. The temperature of the X-ray emitting plasma is cooler compared to dwarf novae, which may suggest a wind is the origin of a significant fraction of the X-ray flux.

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Gavin Ramsay, Peter J. Wheatley, Simon Rosen, Thomas Barclay, Danny Steeghs. 2012-07-05. Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra. https://doi.org/10.1111/j.1365-2966.2012.21660.x

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