CI UMa - SU UMa star

(vsnet-alert 1, 1995 Jan. 9)

Dear Colleagues,

The current outburst of CI UMa was first noticed by J. Pietz, and I observed CI UMa at Ouda Station (Kyoto University) using 60cm refl. + CCD with V filter. By the observation from 15:00 to 21:20 on Jan. 8, 1995, clear superhumps in CI UMa was revealed and CI UMa was idetified as a new member of SU UMa-stars.

The first superhump maximum in my observation came about 16:00 and the amplitude is about 0.21 mag. The preliminary analysis tells the best estimation of Psh is 0.0626 (+- 0.0005) day.

Best Regards,
Daisaku Nogami

(vsnet-obs 894, 1995 Aug. 6)


Following a request from T. Vanmunster, I would like to make some comments on this object, though my information is a little old.

This dwarf nova was discovered by Granskij and Kolotovlina (in Pererm. Zvezdy). They gave seemingly complete description of the outburst behavior.

    JD           mpg    duration
  2441392        14.3   faded by one mag in a day, but then brightened again
                        on 41394, followed by a linear decline until 41400
                        17.0 mag on 41411
    41533        14.8   stayed at maximum for five days.
    41573        15.6   single plate
    41747        15.3   >3
    42097        14.7   >2
    42128        15.6   single plate
    42457        14.6   >4
    42485        15.5   >2
    42751        15.7   single plate
    42890        14.9   >3
    42926        15.2   >3

This object has been included in VSOLJ program since ~1987. A long outburst was observed in Jan. 1988. Serveral other outbursts have been recorded mainly by M. Koshiro.

A photometric period of 87 min in quiescence was detected by Howell et al. (PASP 102, 758). During a bright outburst last year, superhumps were finally discovered by Nogami et al. (Would you please give more details? >Nogami-san)

Taichi Kato


Dear colleagues,

Following a request from T. Vanmunster and T. Kato, I would like to report on the superoutburst in CI UMa in Jan., 1995. This outburst was first found by J. Pietz on Jan. 8.091 (vsnet-obs 12), and we started the time resolved CCD photometry on Jan. 8 at Ouda Station using 0.6m reflector. CI UMa have reached 13.8 mag.

Superhumps have already grown to the amplitude of 0.21 mag. and we could catch four clear superhump maxima during the 6 hours photometry on the first day. The best estimated superhump period is 0.0626 (+- 0.0005) day (see vsnet-alert 1). After that, the secular decline (0.14 mag/day) continued. On Jan. 16, the rapid decline started and the superoutburst came to an end.

Best regards,
Daisaku Nogamisuper, super, super...

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