2012/05/04 by Jeremy Shears, Shears, Jeremy, Robert Koff +16
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astrophysical Phenomena and Observations #FOS: Physical sciences #Gamma-ray bursts and supernovae #Solar and Stellar Astrophysics (astro-ph.SR)
paper · pdf · doi:10.48550/arxiv.1205.0898
openalex publication_date 2012/05/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In 2011 October an optical transient was reported in Pegasus as a possible\nnova. The object had an ultraviolet counterpart, GALEX J215818.5+241924. In\nthis paper we present follow-up photometry of the object which revealed the\npresence of superhumps, with peak-to-peak amplitude of up to 0.22 magnitudes,\ndiagnostic of it being a member of the SU UMa family of dwarf novae. The\noutburst amplitude was 4.6 magnitudes and it lasted at least 10 days, with a\nmaximum brightness of magnitude 14.3. We determined the mean superhump period\nfrom our first 5 nights of observations as Psh = 0.06728(21) d. However\nanalysis of the O-C residuals showed a dramatic evolution in Psh during the\noutburst. During the first part of the plateau phase the period increased with\ndPsh/dt = +2.67(15) x 10-4. There was then an abrupt change following which the\nperiod decreased with dPsh/dt = -2.08(9)x 10-4. We found a signal in the power\nspectrum of the photometry which we tentatively interpret as the orbital signal\nwith Porb = 0.06606(35) d. Thus the superhump period excess was epsilon =\n0.020(8), such value being consistent with other SU UMa systems of similar\norbital period.\n