233 research outputs found
The 2011 February superoutburst of the dwarf nova SDSS J112003.40+663632.4
We report unfiltered photometry of SDSS J112003.40+663632.4 during the 2011
February outburst which revealed the presence of superhumps with peak-to-peak
amplitude of up to 0.22 magnitudes showing this to be an SU UMa type dwarf
nova. The outburst amplitude was 5.4 magnitudes above mean quiescence and it
lasted at least 12 days. The mean superhump period during the plateau phase was
Psh = 0.07057(19) d.Comment: Accepted for publication in the Journal of the British Astronomical
Association. 12 pages, 5 figure
The first confirmed superoutburst of the dwarf nova GALEX J215818.5+241924
In 2011 October an optical transient was reported in Pegasus as a possible
nova. The object had an ultraviolet counterpart, GALEX J215818.5+241924. In
this paper we present follow-up photometry of the object which revealed the
presence of superhumps, with peak-to-peak amplitude of up to 0.22 magnitudes,
diagnostic of it being a member of the SU UMa family of dwarf novae. The
outburst amplitude was 4.6 magnitudes and it lasted at least 10 days, with a
maximum brightness of magnitude 14.3. We determined the mean superhump period
from our first 5 nights of observations as Psh = 0.06728(21) d. However
analysis of the O-C residuals showed a dramatic evolution in Psh during the
outburst. During the first part of the plateau phase the period increased with
dPsh/dt = +2.67(15) x 10-4. There was then an abrupt change following which the
period decreased with dPsh/dt = -2.08(9)x 10-4. We found a signal in the power
spectrum of the photometry which we tentatively interpret as the orbital signal
with Porb = 0.06606(35) d. Thus the superhump period excess was epsilon =
0.020(8), such value being consistent with other SU UMa systems of similar
orbital period.Comment: Accepted for publication in the Journal of the British Astronomical
Association. 10 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1005.5378. Have corrected outburst amplitude, reworded the first 2
sentences of the Abstract for clarity and solved some typo
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