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