Перегляд за Автор "Simon, A."

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  • Ескіз
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    First reported observation of asteroids 2017 SV39, 2017 ST39, and 2017 TS7
    (Одеський національний університет імені І. І. Мечникова, 2023) Simon, A.; Troianskyi, V. V.
    In this paper, we show the result of the joint use of the AZT-8 telescope, the Astrometrica software, and the Väisälä method. The paper considers in detail several of the discovered (rediscovered) asteroids: SV39, 2017 ST39, and 2017 TS7 from a long list of small bodies of the Solar System.
  • Ескіз
    Документ
    Gaia18aak is a new SU UMa-type dwarf nova
    (2019) Simon, A.; Pavlenko, E.; Shugarov, S.; Vasylenko, V.; Izviekova, I.; Reshetnyk, V.; Godunova, V.; Bufan, Yu.; Baransky, A.; Antonyuk, O.; Baklanov, V.; Troianskyi, V.; Udovichenko, Serhii M.; Keir, L.; Удовіченко, Сергій Миколайович; Удовиченко, Сергей Николаевич
    We report the discovery of a new SU UMa-type dwarf nova, Gaia18aak/ AT2018C, based on its optical observations, which were performed at ve observatories (Lisnyky/Kyiv, Terskol, CrAO, Mayaki/Odessa and Star a Lesn a, Slovakia) with six small telescopes. The observational campaign started just after the alert was published by ESA Gaia, DPAC and the Photomet- ric Science Alerts Team (http://gsaweb.ast.cam.ac.uk/alerts); the object was very intensely observed during the rst month. After this there was organized a four-month monitoring in order to test outburst activity of the object. We detected the 0.0647-d (or 0.0692-d) superhump period during ve nights of the superoutburst. Furthermore, we found the only possible outburst during the subsequent 100 nights.
  • Ескіз
    Документ
    MASTER OT J172758.09+380021.5: a peculiar ER UMa-type dwarf nova, probably a missed nova in the recent past
    (2021) Pavlenko, E.; Kato, T.; Antonyuk, K.; Pit, N.; Keir, L.; Udovichenko, Serhii M.; Dubovsky, P.; Sosnovskij, A.; Antonyuk, O.; Shimansky, V.; Gabdeev, M.; Rakhmatullaeva, F.; Kokhirova, G.; Belan, S.; Simon, A.; Baklanov, A.; Kojiguchi, N.; Godunova, V.; Удовіченко, Сергій Миколайович; Удовиченко, Сергей Николаевич
    A CCD photometry of the dwarf nova MASTER OT J172758.09 +380021.5 was carried out in 2019 during 134 nights. Observations covered three superoutbursts, ve normal outbursts and quiescence between them. The available ASASSN and ZTF data for 2014 { 2020 were also examined. Spectral observations were done in 2020 when the object was in quiescence. Spectra and photometry revealed that the star is an H-rich active ER UMa-type dwarf nova with a highly variable supercycle (time interval between two successive superoutbursts) of 50 { 100 d that implies a high and variable mass-transfer rate. MASTER OT J172758.09+380021.5 demonstrated peculiar behaviour: short-lasted superoutbursts (a week); a slow superoutburst decline and cases of rebrightenings; low frequency (from none to a few) of the normal outbursts during the supercycle. In 2019 a mean period of positive superhumps was found to be 0.05829 d during the superoutbursts. Late superhumps with a mean period of 0.057915 d which lasted about 20 d after the end of superoutburst and were replaced by an orbital period of 0.057026 d or its orbital-negative superhump beat period were detected. An absence of eclipse in the orbital light curve and its moderate amplitude are consistent with the orbital inclination of about 40 found from spectroscopy. The blue peaks of the V-Ic and B-Rc colour indices of superhumps during the superoutburst coincided with minima of the light curves, while B-Rc of the late superhumps coincided with a rising branch of the light curves. We found that a low mass ratio q = 0:08 could explain most of the peculiarities of MASTER OT J172758.09+380021.5. The mass-transfer rate should be accordingly higher than what is expected from gravitational radiation only, this assumes the object is in a post-nova state and underwent a nova eruption relatively recently { hundreds of years ago. This object would provide probably the rst observational evidence that a nova eruption can occur even in CVs near the period minimum.