Discovery of five new eclipsing systems of W UMa type

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

Received:   30.12.2019;   accepted:   3.09.2020
(E-mail for contact: alliakos@noa.gr)

Comments:


1. The system USNO-A2.0 1350-03467786 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula HDW 3. USNO-A2.0 1350-03466399 and USNO-A2.0 1350-03461726 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI–MinI ~ MaxI–MinII ~ –0.27 mag in R-filter. The maximum magnitude in R-filter is given in the USNO-A2.0 Catalog (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 1352-0077531. The observations were carried out at the Kryoneri Observatory of the National Observatory of Athens, Corinthia, Greece between September and December 2018 using a 1.2–m prime focus telescope (f/3) equipped with the APOGEE ASPEN CG47 CCD camera and the R (Bessell) photometric filter.

2. The system USNO-A2.0 1275-02644421 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula HaWe 5. USNO-A2.0 1275-02639026 and USNO-A2.0 1275-02643221 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI–MinI = –0.095 mag and MaxI–MinII = –0.09 mag in R-filter. The maximum magnitude in R-filter is given in the USNO-A2.0 Catalog (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 1277-0076480. The observations were carried out at the Kryoneri Observatory of the National Observatory of Athens, Corinthia, Greece between September and December 2018 using a 1.2–m prime focus telescope (f/3) equipped with the APOGEE ASPEN CG47 CCD camera and the R (Bessell) photometric filter.

3. The system USNO-A2.0 0900-14578525 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula NGC 6781. USNO-A2.0 0900-14575744 and USNO-A2.0 0900-14575325 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI–MinI = –0.35 mag and MaxI–MinII = –0.33 mag in R-filter. The maximum magnitude in R-filter is given in the USNO-A2.0 Catalog (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 0966-0493572, 2MASS J19184804+0637562. The observations were carried out at the Kryoneri Observatory of the National Observatory of Athens, Corinthia, Greece between July and September 2018 using a 1.2-m prime focus telescope (f/3) equipped with the APOGEE ASPEN CG47 CCD camera and the R (Bessell) photometric filter.

4. The system USNO-A2.0 1125-16127402 (indicated as V in the finding chart) is located in the Field of View in the FoV of AW Vul and the variable 2MASS J20275736+2453029 (Liakos & Niarchos 2011). The star could also be a delta Sct variable with a dominant period of 0.1536 days. However, J–H = 0.52 from the 2MASS catalogue suggests a rather cool star (K type), therefore the EW-type variability seems more suitable. USNO A2.0 1125-16127586 and USNO A2.0 1125-16126802 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI–MinI ~ MaxI–MinII ~ –0.25 mag in R-filter. The maximum magnitude in R-filter is given in the USNO-A2.0 Catalog (Monet et al. 1998). Other cross identifications for the variable: 2MASS J20291217+2436475. The observations were carried out at the University of Athens Observatory, Athens, Greece in July 2010 using a 20-cm newtonian reflector telescope (f/5) equipped with the SBIG ST-8XME CCD camera and the R (Bessell) photometric filter.

5. The system USNO-A2.0 1425-15515944 (indicated as V in the finding chart) is located in the Field of View of the planetary nebula A66 82 and the variable EG Cas. USNO-A2.0 1425-15522780 and USNO-A2.0 1425-15522749 were used as Comparison (C) and Check (K) stars, respectively, and they are also indicated in the finding chart. MaxI–MinI = –0.53 and MaxI–MinII = –0.49 mag in R-filter. The maximum magnitude in R-filter is given in the USNO-A2.0 Catalog (Monet et al. 1998). Other cross identifications for the variable: NOMAD1 1470-0525441. The observations were carried out at the Kryoneri Observatory of the National Observatory of Athens, Corinthia, Greece between October and November 2017 using a 1.2-m prime focus telescope (f/2.8 using a focal reducer) equipped with the ANDOR ZYLA 5.5 sCMOS camera and the R (Bessell) photometric filter.

Remarks:
In this study, photometric elements of five newly discovered W UMa- type eclipsing binaries are presented for the first time. Their variability was detected for the first time as a by-product during observations of other targets. 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
Liakos, A., Niarchos, P., 2011, Information Bulletin on Variable Stars, 5998, 3
Monet D., Bird A., Canzian B., et al., 1998, USNO-A2.0, A Catalog of Astrometric Standards, (U.S. Naval Observatory, Washington, DC), Centre de Données Astronomiques de Strasbourg, I/252