Discovery of five W UMa systems

A. Liakos
Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Metaxa & Vas. Pavlou St., Penteli, Athens, Greece

Received:   2.12.2019;   accepted:   25.12.2019
(E-mail for contact: alliakos@noa.gr)

Comments:


1. The system USNO-A2.0 1425-02035807 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula Sh2-188. USNO-A2.0 1425-02037041 and USNO-A2.0 1425-02034268 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxII – MinI = –0.27 mag and MaxII – MinII = –0.25 mag in R-filter. The maximum magnitude in R-filter is taken from the USNO-A2.0 Catalogue (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 1484-0055235, 2MASS J01301542+5827315.

2. USNO-A2.0 0975-15174250 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula NGC 6804. USNO-A2.0 0975-15178006 and USNO-A2.0 0975-15178404 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI – MinI = –0.34 mag and MaxI – MinII = –0.29 mag in R-filter. The maximum magnitude in R-filter is taken from the USNO-A2.0 Catalogue (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 0990-0513167, USNO-B1.0 0990-0466422.

3. The system USNO-A2.0 0975-15180095 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula NGC 6804. USNO-A2.0 0975-15178006 and USNO-A2.0 0975-15178404 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI – MinI = –0.23 mag and MaxI – MinII = –0.18 mag in R-filter. The maximum magnitude in R-filter is taken from the USNO-A2.0 Catalogue (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 0990-0513450, 2MASS J19315602+0903459.

4. USNO-A2.0 0975-15180948 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula NGC 6804. USNO-A2.0 0975-15178845 and USNO-A2.0 0975-15179318 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI – MinI = –0.52 mag and MaxI – MinII = –0.46 mag in R-filter. The maximum magnitude in R-filter is taken from the USNO-A2.0 Catalogue (Monet et al. 1998). Other cross identifications for the variable: 2MASS J19315662+0909464, NOMAD1 0991-0512174.

5. The system USNO-A2.0 1425-11417028 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula NGC 7008. USNO-A2.0 1425-11416046 and USNO-A2.0 1425-11415876 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI – MinI = –0.64 mag and MaxI – MinII = –0.63 mag in R-filter. The maximum magnitude in R-filter is taken from the USNO-A2.0 Catalogue (Monet et al. 1998). Other cross identifications for the variable: 2MASS J21000311+5434138.

Remarks:
In the present study, we present the first photometric elements of five newly discovered W UMa-type eclipsing binaries. Their variability was detected for the first time as a by-product during observations of other targets. The observations were carried out at the Kryoneri Observatory of the National Observatory of Athens, Corinthia, Greece between November 2017 – September 2019 using a 1.2–m prime focus telescope (f/3) equipped with the APOGEE ASPEN CG47 CCD camera and the red (Bessell) photometric filter. The observations of USNO-A2.0 1425-02035807 in 2017 were made with the same telescope and camera set-up, but without filters. The system USNO-A2.0 1425-11417028 was also observed in 2019 with the same telescope and the Andor sCMOS Zyla 5.5 camera equipped with the red (Bessell) photometric filter. Differential magnitudes were obtained for all targets using the software Muniwin v.1.1.29 (Hroch 1998).

References:
Hroch, F., 1998, Proceedings of the 29th Conference on Variable Star Research, 30
Monet, D., Bird, A., Canzian, B., et al., 1998, USNO-A2.0, A Catalogue of Astrometric Standards (U.S. Naval Observatory, Washington, DC), Centre de Données Astronomiques de Strasbourg, I/252