Re-appearance of optical flickering from RS Oph

ATel #15330; R. Zamanov, V. Marchev (Bulgarian Academy of Sciences), D. Marchev, T. Atanasova, N. Pavlova (Shumen University)
on 14 Apr 2022; 09:55 UT
Credential Certification: R. K. Zamanov (rkz@astro.bas.bg)

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We observed intra-night variability of RS Oph in Sloan g' and r' bands with the 40 cm telescope of the Shumen University "Episkop Konstantin Preslavski", Bulgaria (Kjurkchieva et al. 2020, BlgAJ, 32, 113) on 2022 April 14. The field of view was 30x30 arcmin and the resolution was 0.61 arcsec/pixel. For 142 minutes continuous observations, we obtained 152 exposures of 15 sec in g' band, and 160 of 10 sec in r' band. We performed standard aperture photometry with aperture size 3.5 arcsec using 4 comparison stars around RS Oph.

We do detect optical flickering on minute-to-hour time scale with peak-to-peak amplitude 0.21 mag in g' band and 0.17 mag in r' band (see Fig. 1).

The latest outburst of the recurrent nova RS Oph occurred in August 2022. The time of the eruption is estimated to be at JD2459435.0 = 2021 Aug 08.50 (Munari & Valisa, 2021, arXiv:2109.01101). The flickering variability disappeared after the 2021 outburst, as a result of the destruction of the accretion disc by nova outburst. The flickering was missing on 24 March 2022 (day 227 of the 2021 outburst; ATel #15296) and is present on 14 April 2022 (day 248).

These observations indicate re-establishment of accretion between 227 and 248 days after the onset of the 2021 outburst.

Acknowledgements: projects KP-06-H28/2 and RD-08-100/2022.

Optical flickering of RS Oph observed on 14 April 2022.