Discovery of Deep Eclipses in the Cataclysmic Variable ZTF17aaaeefu (2MASS J00594349+6454419)

I performed photometric observations of the cataclysmic variable candidate ZTF17aaaeefu and discovered very deep eclipses. The observations were obtained over 8 nights covering 7 months. The eclipse profile is similar to the eclipse profiles observed in other cataclysmic variables. During the observations, ZTF17aaaeefu showed brightness changes resembling dwarf nova outbursts and quiescent states. When ZTF17aaaeefu was bright (16.0–16.2 mag), the average eclipse depth was 2.50 ± 0.18 mag. When ZTF17aaaeefu was faint (17.2–17.4 mag), the average eclipse depth was 1.45 ± 0.06 mag. However, these differences in the eclipse depth may be mainly caused by the contaminating effect of three faint stars around ZTF17aaaeefu. In both cases, the average width of the prominent parts of the eclipses was the same and was about 30 min. Due to the large coverage of observations, I measured the orbital period with high precision, Porb=0.18821155±0.00000014 d. I derived the eclipse ephemeris, the validity time of which is 700 years in accordance with the precision of the orbital period. This ephemeris can be used for future studies of the orbital period changes. Because ZTF17aaaeefu has a long orbital period, this cataclysmic variable is of interest for determining the masses of its stellar components. In future radial velocity measurements, my precise eclipse ephemeris may be useful for determining the orbital phases. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.This work was supported in part by the Ministry of Science and Higher Education of the Russian Federation, FEUZ-2020-0030, and by the Act no. 211 of the Government of the Russian Federation, agreement no. 02.A03.21.0006. This research has made use of NASA’s Astrophysics Data System Bibliographic Services and the International Variable Star Index (VSX) database. The VSX database is operated at AAVSO, Cambridge, Massachusetts, USA. This research has made use of the VizeR catalogue access tool (Ochsenbein et al. ) and the Aladin sky atlas developed at CDS, Strasbourg observatory, France (Bonnarel et al. ; Boch and Fernique ). This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium ). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement