Gaia23cer: a polar with deep eclipse
ATel #16249; A. Sosnovskij (Crimean astrophysical observatory), E. Pavlenko (Crimean astrophysical observatory), A. Simon (ASPD TShNU of Kyiv), S. Shugarov (Astronomical Institute of Slovak Academy of Sciences, Tatranska Lomnica)
on 20 Sep 2023; 19:17 UT
Credential Certification: Andrew Simon (skazhenijandrew@gmail.com)
Subjects: Optical, Binary, Cataclysmic Variable, Transient, Variables
As a CV candidate Gaia23cer(ZTF18abunixr) was mentioned for the first time in (FORSTER, F., et al., 2021, The Astronomical Journal, 161.5: 242.) and on 2023-08-31 was rediscovered by Gaia Alerts team (S.T. Hodgkin, E. Breedt, A. Delgado, D.L. Harrison, M. van Leeuwen, G. Rixon, T. Wevers, A. Yoldas (IoA Cambridge), N. Ihanec, K. Kruszynsk, K.A. Rybicki, L. Wyrzykowski (Warsaw University Astronomical Observatory), Z. Kostrzewa-Rutkowska (Leiden Observatory), D. Eappachen (SRON/RU), G. Marton (Konkoly Observatory)). Simon et al. (ATel #16240) first detected a 0.071-d orbital period of brightness variations, displaying a strong eclipse. Authors preliminary suggested this CV to be the SU UMa-type star. According to Gaia DR3 data, a distance to this object is about 250 pc.
Subsequent BVRcIc observations of Gaia23cer were made at the 2.6-m mirror Shajn telescope of the Crimean astrophysical observatory on HJD 2460201.43-2460201.59. The object in maximum light had B= 17.0, V=16.0, Rc=15.2, Ic=14.5 (Fig.1). Additional observations were made on HJD 2460203.41-.63 and 2460205.43-.48 in Rc band at the Zeiss-600 (Tatranska Lomnica). The timings of the mid-eclipse of these data combined with those obtained with 0.70-m telescope of Lisnyky observation station (ATel #16240) made it possible to calculate the ephemeris for the mid-eclipse: HJD Min=2460201.4361+0.07087xE. BVRcIc data folded on this period showed that the depth of the eclipse is about 5 mag in BVRc and about 3 mag in Ic. Eclipse duration is ~7.6 min. The light curve displayed a two-humped shape where the eclipse occurred at the rising branch of the smaller hump. The amplitude of a bigger hump increased from B (0.6 mag) to Ic (1.4 mag). The red color of Gaia23cer, large amplitude in Rc and Ic, the light curve profile features and small period indicate this CV is a one-pole accreting polar. Its light curve partially resembles those of the polar BS Tri (Kolbin et al., 2022, MNRAS, 511, 20).
The spectroscopy and polarimetry of Gaia23cer are necessary to obtain the physical parameters of this deep eclipsing polar.
