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KS UMa superhumps update Dear Colleagues, We have received new sets of data from Nakajima-san and Jochen Pietz, and a revised set from the Nyrola team. New data by the Kyoto team and Torii-san (RIKEN) are continuously produced. From these observations, the amplitude of the superhumps apparently reached a maximum (0.30 mag) on Feb. 20, and is now slowly decalying. The best superhump period from the combined data set is 0.07037(3) d. Although there is a slight tendency of a period decrease during this period, no striking period change as recorded in UV Gem was observed. The new superhump period is significantly longer than those previously reported (P=0.0697(1) d, Tonny Vanumunster, vsnet-alert 1448, etc.). The difference amounts almost 1%, which is exceptionally large among known variations of the superhump period in SU UMa-type dwarf novae. It may have been possible that there was an error in cycle count determination during the past superoutbursts; otherwise the object can be a rare object showing unusually large variations in the superhump periods. In UV Gem, a similar inconsistency has been recently positively resolved as an effect of large change in period (cf. vsnet-campaign-dn 3307). Further observations of KS UMa during the present very favorable superoutburst are thus most strongly encouraged in order to completely follow the period evolution. Regards, Taichi Kato VSNET Collaboration team
Return to the Powerful Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
