SW UMa: Superoutburst in October-November
P. Schmeer and E. Muyllaert reported an outburst of SW UMa on October 24
(vsnet-campaign-dn
2915, 2916,
2917,
2920).
T. Kato reported the appearance of 0.1-mag likely superhump-type features
during a rising phase observed by K. Tanabe on October 24 (vsnet-campaign-dn
2924, 2927).
The superhumps were growing on Oct. 24, and reached an amplitude of 0.1
mag on Oct. 25. Short-term (minutes) modulations were furthermore superimposed,
which may be QPOs (super-QPOs) (vsnet-campaign-dn
2929). The light curve taken by K. Torii on October 27 showed the fully
grown superhumps (0.2 mag)(vsnet-campaign-dn
2937, 2940).
L. Kral reported that T. Hynek also confirmed superhumps of 0.2mag on
October 26/27 (vsnet-campaign
1346). On October 28, superhumps observed by K. Tanabe further increased
in amplitude (0.25mag) (vsnet-campaign-dn
2943). The Oct. 29 data showed the presence of (super)QPOs with a typical
period of 3-4 min, although the phenomenon was not as striking as in the
1992 one (vsnet-campaign-dn
2957).
Secondary superhumps appeared on Nov. 1 (vsnet-campaign-dn
2984). On November 3, the amplitude of the superhumps once reached
a minimum (vsnet-campaign-dn
2999). On Nov. 4, the superhumps had double maxima with complex substructures.
There was an indication of high-amplitude QPOs of ~5 min (vsnet-campaign-dn
2986, 2999).
The Nov. 5 observation by K. Tanabe and K. Torii clearly showed the regrowth
of the superhumps. The profile showed nightly changes, -- from doubly peaked
to sharp triangular shape -- which even looks like a "miniature WZ Sge"
(vsnet-campaign-dn
2990, 2999).
The object entered a rapid fading stage from the superoutburst on November
9 (vsnet-campaign-dn
2974, 2981,
2992,
3001,
3006,
3007,
3014).
The data on November 9 taken by K. Tanabe showed a precipitous fading (1.9
mag/d) and superimposed very complex variations, some of which can be superhumps,
late superhumps, or QPOs (vsnet-campaign-dn
3009). The data just before a rapid fading taken by K. Torii, clearly
indicated the late-stage superhumps with diminishing amplitudes (vsnet-campaign-dn
3021). QPOs were prominent during the rapidl fading phase. This finding
confirmed the 2000 finding that super-QPOs became prominent during the decline
phase from a superoutburst (vsnet-campaign-dn
3025).
On Nov. 10, the rapid fading stopped. There was a prominent hump feature
(0.5 mag), which was likely a late superhump (vsnet-campaign-dn
3023). The large amplitude QPOs (periods 3-4 min) were also still prominent
(vsnet-campaign-dn
3024). On November 12, short-period variations became less prominent.
On November 13, the variation became stronger again (0.1-0.4 mag) (vsnet-campaign-dn
3031). On Nov. 16, SW UMa seems to have become slightly brighter than
on the previous nights, breaking the slow declining trend. Short-term
variations with time-scales of 10-20 min were strongly present. Some of
them seem to show some degree of coherence (vsnet-campaign-dn
3039). The object kept its post-superoutburst magnitude level on November
19. A new humps having a superhump-like profile appeared on November 19,
although the period is different from ordinary superhumps or late superhumps
(vsnet-campaign-dn
3043).
Other articles:
vsnet-campaign-dn
2922, 2932,
2945,
2948
Link:
Light curve taken by T. Hynek:
http://ostrava.astronomy.cz/endetails.php?id=129
[vsnet-campaign
1346]