Gaia22dbc: a new SU UMa-type dwarf nova during its ongoing superoutburst
ATel #17981; A. O. Simon (ASPD TShNU of Kyiv), S. A. Simon-Reshetnik (ASPD TShNU of Kyiv), D. Yu. Rusanova (ASPD TShNU of Kyiv), A. V. Grytsai (ASPD TShNU of Kyiv), M. V. Matiushenko (ASPD TShNU of Kyiv), A. Yu. Korosko (ASPD TShNU of Kyiv), P. J. Mikolajczyk (U. Wroclaw/NCBJ, PL), {\L}. Wyrzykowski (U. Warsaw/NCBJ, PL/EASST. eu), K. Kotysz (U. Wroclaw/U. Warsaw, PL), Y. V. Rudnieva (ASPD TShNU of Kyiv)
on 17 Aug 2026; 20:25 UT
Credential Certification: Andrew Simon (skazhenijandrew@gmail.com)
Subjects: Optical, Request for Observations, Cataclysmic Variable, Star, Transient, Variables
Gaia22dbc/ASASSN-15qa/AT 2022qcr was identified by our Outbursts Alerting System as a promising candidate for an SU UMa-type dwarf nova.
Analysis of its long-term light curve revealed, in addition to relatively short outbursts lasting about 4 days, two substantially longer outbursts that are likely superoutbursts. The first long outburst occurred in March 2018 and lasted about 22 days, with possible rebrightenings. The second occurred in June-July 2022, lasting about 18 days, with a 5-day precursor and a 3-day rebrightening. A new outburst began approximately 8 days before our observations. Given its duration and the characteristics of the previously identified long outbursts, we considered the current event a likely superoutburst.
Therefore, time-resolved photometric observations were carried out with the 0.7-m f/4 AZT-8 telescope at the Observational Station Lisnyky of Taras Shevchenko National University of Kyiv to search for superhumps.
The observations covered the interval from MJD 61268.79933 to 61268.97566, corresponding to approximately 4.2h (Fig. 1). The resulting light curve revealed clear periodic modulations with a period of 0.1030(73)d (Fig. 2) and a peak-to-peak amplitude of approximately 0.25m (Fig. 3). The superhump period was determined using a Lomb-Scargle periodogram implemented in scipy.signal.lombscargle. Given the measured superhump period of 0.1030d, the orbital period of the system is likely to lie within the period gap. All materials related to this observation are available on A.O. Simon's personal website.
The detection of superhumps provides strong evidence that the object is a new SU UMa-type dwarf nova during its ongoing superoutburst.
Further observations are strongly encouraged. Observers are invited to upload their observations to the object's BHTOM page, where all submitted data are automatically processed: https://bhtom.space/public/targets/Gaia22dbc.
BHTOM is based on the open-source TOM Toolkit by LCO and has been developed with funding from the OPTICON-RadioNet Pilot (ORP) of the European Union's Horizon 2020 research and innovation programme under grant agreement No 101004719 (2021-2025). This project has received funding from the European Union's Horizon Europe Research and Innovation programme ACME under grant agreement No 101131928 (2024-2028).
