IY UMa: Superoutburst in May
In April, T. Kato commented that a superoutburst of the eclipsing SU UMa
star IY UMa would occur soon, and encouraged close monitoring (vsnet-campaign-dn
2267). A. Oksanen reported that the object was brighter (17.5mag) on
April 21 than usual (vsnet-campaign-dn
2314, 2326).
A. Oksanen reported that the object was still calm at 17.5mag on April
21 (vsnet-campaign-dn
2332).
On May 7, the superoutburst was actually detected (vsnet-campaign-dn
2362, 2364,
2366).
The light curve taken by L. Cook on May 8 showed superhumps with a complex
structure. T. Kato noticed that the overall light curve resembles that
of DV UMa on the first night of the 1999 superoutburst (vsnet-campaign-dn
2379). Superhumps were observed to increase in amplitude in the early
May 11, when their amplitude reached to 0.8mag (vsnet-campaign-dn
2390). During the very early phase of the superoutburst, the period
of superhump was relatively short (0.07500 d), and then the superhump
period increased with time. The data on May 10-11 shows a superhump period
of 0.07643 d (vsnet-campaign-dn
2391, 2396).
The light curve on May 11-13 showed superhumps with the period of 0.07584(4)
d. It indicates that the period was decreasing at that time (vsnet-campaign-dn
2405).
On May 17, the light curve showed "triple" humps which may come from ordinary
superhumps and late superhumps (vsnet-campaign-dn
2418). On May 19, the superhumps was doubly peaked, but the secondary
maxima seem to occur earlier than what are expected for late superhumps
(vsnet-campaign-dn
2434). A rapid fading started on May 22 (vsnet-campaign-dn
2442). Possible late superhumps were seen on the light curve on May
23 (vsnet-campaign-dn
2458). M. Uemura reported that it was still slightly above the quiescent
level on May 24 (vsnet-campaign-dn
2452).
A possible outburst was reported on July 28, but no major outburst was
confirmed (vsnet-campaign-dn
2680).
According to T. Kinnunen, IY UMa experienced a new outburst of 14.2mag on
December 21 (vsnet-campaign-dn
3165). A. Oksanen reported that they detected three eclipses with a
smoothly fading trend on December 22. All three eclipses were about 2 minutes
ahead of the predicted time (vsnet-campaign-dn
3179). The object then faded quickly. It was a normal outburst (vsnet-campaign-dn
3182).
Other articles:
vsnet-campaign-dn
2371,2327,
2372,
2373,
2377,
2381,
2382,
2383,
2384,
2386,
2387,
2393,
2394,
2376,
2363,
2375,
2398,
2406,
2411,
2415,
2420,
2435