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EF Peg: Summary of the plateau phase
We performed time-series data sets of EF Peg during the last
superoutburst. To date, the VSNET team has obtained the light curves
on October 6 (Kyoto team), 7 (D. Starkey, Kyoto team), 12 (J. Pietz,
Kyoto team), 13, 14, 15, and 18 (Kyoto team); total 2444 useful points.
When we performed period analysis using the above all data sets,
the best candidate of the period is calculated to be 0.086509 (24) d.
During the early phase, the deline rate was relatively fast
(~0.1mag/d). Of course, it may be temporary since we have only two days
data on October 6 and 7. The D. Starkey's data of 1.5 hours clearly
shows humps. While the baseline is not so long, we can see possible two
hump peaks in his data, which indicates that the period is shorter
than the late phase and/or the profile is double-peak.
During the late phase, the decline rate became more gradual
(<0.1mag/d) and not monotonic. When we use only this phase, the period
analysis yields a period of 0.086686 (34) d which is significantly
longer than that included the early phase. Our preliminary O-C analysis
of hump peaks indicates a possible gradual period shortening during
the late phase.
Additional data sets, if exist, will be very useful for more detailed
analysis of this rare outburst of EF Peg. We will welcome any data if
you collaborate with us. Pleae note that the event is not completely
finished. We encouraged to monitor possible re-brightenings.
Average differential magnitudes taken at Kyoto:
HJD-2400000 dif. mag. err N
52189.173546 1.275797 0.009991 143
52190.179557 1.379093 0.006102 225
52195.177101 1.696861 0.002629 266
52196.176637 1.708587 0.004087 327
52197.144994 1.756763 0.002525 646
52198.133880 1.828768 0.003439 125
52201.116116 1.930902 0.001570 512
Regards,
Makoto Uemura
on behalf of VSNET collaboration team
Return to the Powerful Daisaku
vsnet-adm@kusastro.kyoto-u.ac.jp
