Detection of positive superhumps in the cataclysmic variable KR Aur

ATel #16960; N. Antonov (AAVSO member, Bulgaria), S. Boeva (IA and NAO, BAS, Bulgaria), R. Zamanov (IA and NAO, BAS, Bulgaria)
on 24 Dec 2024; 16:47 UT
Credential Certification: R. K. Zamanov (rkz@astro.bas.bg)

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We report a detection of positive superhumps in the light curve of the cataclysmic variable star KR Aur. KR Aur is currently in an intermediate state with an average V magnitude ~ of 16.4. Photometric observations were carried out on December 17, 19 and 22, 2024. The observations were performed in V-band from the “Meshtitsa” Amateur Observatory, Pernik, Bulgaria, at an exposure of 300 seconds with a 0.25-m Newtonian telescope (F/4.8), an ASI533MM Pro CMOS camera, and Baader photometric filters. The resulting data include over 13.1 hours of observations in a time span of 5.1 days. The photometry was done in AAVSO VPhot using comparison stars from AAVSO. The average photometric error is 0.044 mag. The period analysis with the Lomb-Scargle algorithm implemented in the Peranso software resulted in 0.169147 +/- 0.001736 d, which is about 4 % longer than the orbital period (Rodríguez-Gil et al., 2020, MNRAS, 494, 425). The data were also tested with other algorithms (see Fig. 1) such as ANOVA, PDM, and DCTFT and all showed similar results (0.1690-0.1696 d). Phased curve is shown in Fig. 2. Positive superhumps are common properties of dwarf novae and other CVs, but never has been detected in KR Aur light curves (Bruch, 2023, MNRAS, 519, 352). Establishing the moments of appearance and disappearance of these superhumps is important.

Periodograms and phased curve for KR Aur