* Astronomy

The cataclysmic binary CR Bootis is in outburst.

Date: 16th May, 2011
Magnitude range: 13.0 - 17.5 V
Period: ?
Satellite period: 0.017029 days
Type: AM. Herculi (?)

Position (2000): RA 13 48 55.22, Dec +07 57 35.8


CR Bootis is an enigmatic blue variable star with rapid photmetric variations and a spectrum dominated by helium. It consists of two white dwarfs in close orbit, with a probable underlying binary period of 1471 s. For years we have marvelled at the star's large nightly variations - ramping up or down at a rate of ~0.1/hr. An intensive photometry campaign in 1996 showed that this variability is cyclic with a quasiperiod of about 19 hr, and demonstrated association of 14990 s photometric variations ("superhumps") with extended bright states ("superoutbursts").
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