Outburst of CC Cnc

(from AAVSO NEWS FLASH No. 18)


The dwarf nova type (U Gem subclass) cataclysmic variable CC Cnc is 
in outburst as indicated by the following observations:

                                       AAVSO Observer
    UT             JD        Mag.        Initials

MAY 7.0743    2450210.5743   14.5          BRJ    
MAY 7.1958    2450210.6958  <13.3          BTH    
MAY 8.1972    2450211.6972   13.5          BTH    
MAY 9.2299    2450212.7299   13.1          BTH    

The last outburst of this star began on March 22, 1995 and reached 
magnitude 13.2 at maximum on March 25.

Detection of superhumps

(vsnet-alert 415, T. Kato)

As already reported in the AAVSO News Flash No. 18, the dwarf nova CC Cnc is undergoing an outburst. V-band CCD photometry at Ouda Staion (Kyoto University) has revealed clear superhumps with an amplitude of 0.28 mag.

    mid-UT    V-C   S.D.   N  band    V-mag
  ---------------------------------   -----
  960514.496  2.091 0.084  55 V       13.99
  960515.482  2.209 0.090  76 V       14.11

  comparison: VSNET 11.90
  instruments: 60-cm telescope + CCD + V-filter
  observers: T. Kato and D. Nogami

Determination of the superhump period is rather difficult due to the short observing window. The most probable period is 0.0759 day, or its one-day alias 0.0820 day. This finding has confirmed earlier detection of superhump-like variations during the 1993 Feb. outburst through insufficient sky conditions. Re-analysis of the latter data gives a period of 0.0761 (or 0.0822, less likely) day. The present observations seem to preclude the clamied orbital period of 0.0942 day (Munari et al. 1990, IAUC No. 5024), which has entitled CC Cnc a rare dwarf nova in the CV period gap.

Follow-up observations at different longitudes are encouraged.

Taichi Kato and Ouda team

Chart and CCD image


(submitted to PASJ)

TeX files and figures

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